diff --git a/build.gradle b/build.gradle
index ba95b65..6b05b21 100644
--- a/build.gradle
+++ b/build.gradle
@@ -16,12 +16,6 @@
  * - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
  */
 
-group = "com.github.fge";
-version = "0.2.1-SNAPSHOT";
-description = "A library for handling large text files as CharSequences";
-sourceCompatibility = "1.7";
-targetCompatibility = "1.7"; // defaults to sourceCompatibility
-
 /*
  * This has to be here... It will not be taken into account in common.gradle!
  *
@@ -31,7 +25,7 @@ targetCompatibility = "1.7"; // defaults to sourceCompatibility
  */
 buildscript {
     repositories {
-        maven { url "http://repo.spring.io/plugins-release" };
+        maven { url "https://repo.spring.io/plugins-release" };
         mavenCentral();
     }
     dependencies {
@@ -46,7 +40,6 @@ buildscript {
 apply(plugin: "java");
 apply(plugin: "maven");
 apply(plugin: "signing");
-apply(plugin: "osgi");
 apply(plugin: "idea");
 apply(plugin: "eclipse");
 apply(plugin: "propdeps");
@@ -55,6 +48,12 @@ apply(plugin: "propdeps-idea");
 apply(plugin: "propdeps-eclipse");
 apply(plugin: "info.solidsoft.pitest");
 
+group = "com.github.fge";
+version = "0.2.1-SNAPSHOT";
+description = "A library for handling large text files as CharSequences";
+sourceCompatibility = "1.7";
+targetCompatibility = "1.7"; // defaults to sourceCompatibility
+
 /*
  * Repositories to use
  */
@@ -68,14 +67,15 @@ repositories {
 dependencies {
     provided(group: "com.google.code.findbugs", name: "jsr305",
         version: "3.0.0");
-    compile(group: "com.google.guava", name: "guava", version: "18.0");
+    compile(group: "com.google.guava", name: "guava", version: "30.1-android");
     testCompile(group: "org.testng", name: "testng", version: "6.8.13") {
         exclude(group: "junit", module: "junit");
         exclude(group: "org.beanshell", module: "bsh");
         exclude(group: "org.yaml", module: "snakeyaml");
     };
     testCompile(group: "org.mockito", name: "mockito-core", version: "1.10.17");
-    testCompile(group: "org.assertj", name: "assertj-core", version: "1.7.0");
+    testCompile(group: "org.assertj", name: "assertj-core", version: "2.9.1");
+    testCompile(group: "org.apache.commons", name: "commons-lang3", version: "3.11")
 }
 
 test {
@@ -99,6 +99,10 @@ task sourcesJar(type: Jar, dependsOn: classes) {
 
 javadoc {
     options.overview = "src/main/java/overview.html";
+    // https://github.com/gradle/gradle/issues/11182
+    if (JavaVersion.current().compareTo(JavaVersion.VERSION_1_7) > 0) {
+        options.addStringOption("-release", "7")
+    }
 }
 
 task javadocJar(type: Jar, dependsOn: javadoc) {
@@ -106,9 +110,9 @@ task javadocJar(type: Jar, dependsOn: javadoc) {
     from javadoc.destinationDir;
 }
 
-javadoc.options.links("http://docs.oracle.com/javase/7/docs/api/");
-javadoc.options.links("http://jsr-305.googlecode.com/svn/trunk/javadoc/");
-javadoc.options.links("http://docs.guava-libraries.googlecode.com/git-history/v17.0/javadoc/");
+javadoc.options.links("https://docs.oracle.com/javase/7/docs/api/");
+javadoc.options.links("https://static.javadoc.io/com.google.code.findbugs/jsr305/3.0.2/");
+javadoc.options.links("https://static.javadoc.io/com.google.guava/guava/17.0/");
 
 artifacts {
     archives jar;
@@ -116,13 +120,10 @@ artifacts {
     archives javadocJar;
 }
 
-task wrapper(type: Wrapper) {
-    gradleVersion = "2.2.1";
-    distributionUrl = "http://services.gradle.org/distributions/gradle-${gradleVersion}-all.zip";
-}
-
-task pom << {
-    pom {}.writeTo("${projectDir}/pom.xml");
+task pom {
+    doLast {
+        pom {}.writeTo("${projectDir}/pom.xml");
+    }
 }
 
 /*
@@ -137,18 +138,20 @@ project.ext {
     sonatypeSnapshots = "https://oss.sonatype.org/content/repositories/snapshots/";
 };
 
-task checkSigningRequirements << {
-    def requiredProperties = [ "sonatypeUsername", "sonatypePassword" ];
-    def noDice = false;
-    requiredProperties.each {
-        if (project.properties[it] == null) {
-            noDice = true;
-            System.err.printf("property \"%s\" is not defined!")
+task checkSigningRequirements {
+    doLast {
+        def requiredProperties = [ "sonatypeUsername", "sonatypePassword" ];
+        def noDice = false;
+        requiredProperties.each {
+            if (project.properties[it] == null) {
+                noDice = true;
+                System.err.printf("property \"%s\" is not defined!")
+            }
         }
+        if (noDice)
+            throw new IllegalStateException("missing required properties for " +
+                    "upload");
     }
-    if (noDice)
-        throw new IllegalStateException("missing required properties for " +
-            "upload");
 }
 
 uploadArchives {
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 3c7abdf..e708b1c 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index a6f592b..4d9ca16 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,5 @@
-#Fri Feb 28 09:30:03 CET 2014
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=http\://services.gradle.org/distributions/gradle-1.11-all.zip
diff --git a/gradlew b/gradlew
index 91a7e26..4f906e0 100755
--- a/gradlew
+++ b/gradlew
@@ -1,4 +1,20 @@
-#!/usr/bin/env bash
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
 
 ##############################################################################
 ##
@@ -6,20 +22,38 @@
 ##
 ##############################################################################
 
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS=""
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
 
 APP_NAME="Gradle"
 APP_BASE_NAME=`basename "$0"`
 
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"
 
-warn ( ) {
+warn () {
     echo "$*"
 }
 
-die ( ) {
+die () {
     echo
     echo "$*"
     echo
@@ -30,6 +64,7 @@ die ( ) {
 cygwin=false
 msys=false
 darwin=false
+nonstop=false
 case "`uname`" in
   CYGWIN* )
     cygwin=true
@@ -40,33 +75,14 @@ case "`uname`" in
   MINGW* )
     msys=true
     ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
 esac
 
-# For Cygwin, ensure paths are in UNIX format before anything is touched.
-if $cygwin ; then
-    [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
-fi
-
-# Attempt to set APP_HOME
-# Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
-done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >&-
-APP_HOME="`pwd -P`"
-cd "$SAVED" >&-
-
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
+
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
@@ -90,7 +106,7 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
     MAX_FD_LIMIT=`ulimit -H -n`
     if [ $? -eq 0 ] ; then
         if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
@@ -110,11 +126,13 @@ if $darwin; then
     GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
 fi
 
-# For Cygwin, switch paths to Windows format before running java
-if $cygwin ; then
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
     APP_HOME=`cygpath --path --mixed "$APP_HOME"`
     CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
 
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
     # We build the pattern for arguments to be converted via cygpath
     ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
     SEP=""
@@ -138,27 +156,30 @@ if $cygwin ; then
         else
             eval `echo args$i`="\"$arg\""
         fi
-        i=$((i+1))
+        i=`expr $i + 1`
     done
     case $i in
-        (0) set -- ;;
-        (1) set -- "$args0" ;;
-        (2) set -- "$args0" "$args1" ;;
-        (3) set -- "$args0" "$args1" "$args2" ;;
-        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
     esac
 fi
 
-# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
-function splitJvmOpts() {
-    JVM_OPTS=("$@")
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
 }
-eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
-JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
 
-exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
index aec9973..ac1b06f 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -1,3 +1,19 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
 @if "%DEBUG%" == "" @echo off
 @rem ##########################################################################
 @rem
@@ -8,20 +24,23 @@
 @rem Set local scope for the variables with windows NT shell
 if "%OS%"=="Windows_NT" setlocal
 
-@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=
-
 set DIRNAME=%~dp0
 if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if "%ERRORLEVEL%" == "0" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -35,7 +54,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -45,34 +64,14 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windowz variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-if "%@eval[2+2]" == "4" goto 4NT_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-goto execute
-
-:4NT_args
-@rem Get arguments from the 4NT Shell from JP Software
-set CMD_LINE_ARGS=%$
-
 :execute
 @rem Setup the command line
 
 set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
+
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
diff --git a/src/main/java/com/github/fge/largetext/ClosableCharSequence.java b/src/main/java/com/github/fge/largetext/ClosableCharSequence.java
new file mode 100644
index 0000000..f53786e
--- /dev/null
+++ b/src/main/java/com/github/fge/largetext/ClosableCharSequence.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2014, Francis Galiegue (fgaliegue@gmail.com)
+ *
+ * This software is dual-licensed under:
+ *
+ * - the Lesser General Public License (LGPL) version 3.0 or, at your option, any
+ *   later version;
+ * - the Apache Software License (ASL) version 2.0.
+ *
+ * The text of both licenses is available under the src/resources/ directory of
+ * this project (under the names LGPL-3.0.txt and ASL-2.0.txt respectively).
+ *
+ * Direct link to the sources:
+ *
+ * - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt
+ * - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
+ */
+
+package com.github.fge.largetext;
+
+import java.io.Closeable;
+
+/**
+ * {@link CharSequence} that has underlying resource that should be closed
+ * (thus {@link Closeable#close()} should be implemented).
+ */
+public interface ClosableCharSequence
+        extends CharSequence, Closeable
+{
+}
diff --git a/src/main/java/com/github/fge/largetext/LargeText.java b/src/main/java/com/github/fge/largetext/LargeText.java
index 957bc4e..89492dd 100644
--- a/src/main/java/com/github/fge/largetext/LargeText.java
+++ b/src/main/java/com/github/fge/largetext/LargeText.java
@@ -24,6 +24,7 @@
 import com.github.fge.largetext.range.IntRange;
 import com.github.fge.largetext.sequence.CharSequenceFactory;
 import com.google.common.base.Preconditions;
+import com.google.common.base.Supplier;
 
 import javax.annotation.Nonnull;
 import javax.annotation.ParametersAreNonnullByDefault;
@@ -31,7 +32,7 @@
 import java.io.IOException;
 import java.nio.CharBuffer;
 import java.nio.channels.FileChannel;
-import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
 import java.util.List;
 import java.util.Map;
 import java.util.logging.Logger;
@@ -86,7 +87,7 @@
  */
 @ParametersAreNonnullByDefault
 public abstract class LargeText
-    implements CharSequence, Closeable
+    implements ClosableCharSequence
 {
     private static final Logger LOGGER
         = Logger.getLogger(LargeText.class.getCanonicalName());
@@ -102,22 +103,22 @@ public abstract class LargeText
      * The only protected constructor
      *
      * @param channel the {@link FileChannel} to the (hopefully text) file
-     * @param charset the character encoding to use
+     * @param decoderSupplier the character decoder to use
      * @param quantity the quantity of size units
      * @param sizeUnit the size unit
      * @throws IOException failed to build a decoder
      */
-    protected LargeText(final FileChannel channel, final Charset charset,
+    protected LargeText(final FileChannel channel, final Supplier<CharsetDecoder> decoderSupplier,
         final int quantity, final SizeUnit sizeUnit)
         throws IOException
     {
         this.channel = Preconditions.checkNotNull(channel,
             "file channel cannot be null");
-        Preconditions.checkNotNull(charset, "charset cannot be null");
+        Preconditions.checkNotNull(decoderSupplier, "charset decoder supplier cannot be null");
         Preconditions.checkNotNull(sizeUnit, "size unit cannot be null");
         final long windowSize = sizeUnit.sizeInBytes(quantity);
-        decoder = new TextDecoder(channel, charset, windowSize);
-        loader = new TextCache(channel, charset);
+        decoder = new TextDecoder(channel, decoderSupplier, windowSize);
+        loader = new TextCache(channel, decoderSupplier);
         factory = new CharSequenceFactory(decoder, loader);
     }
 
diff --git a/src/main/java/com/github/fge/largetext/LargeTextFactory.java b/src/main/java/com/github/fge/largetext/LargeTextFactory.java
index d1fb3e8..11484ce 100644
--- a/src/main/java/com/github/fge/largetext/LargeTextFactory.java
+++ b/src/main/java/com/github/fge/largetext/LargeTextFactory.java
@@ -19,6 +19,7 @@
 package com.github.fge.largetext;
 
 import com.google.common.base.Preconditions;
+import com.google.common.base.Supplier;
 
 import javax.annotation.Nonnull;
 import javax.annotation.concurrent.Immutable;
@@ -26,6 +27,7 @@
 import java.io.IOException;
 import java.nio.channels.FileChannel;
 import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.OpenOption;
 import java.nio.file.Path;
@@ -70,7 +72,7 @@
 @Immutable
 public final class LargeTextFactory
 {
-    private final Charset charset;
+    private final Supplier<CharsetDecoder> decoderSupplier;
     private final SizeUnit sizeUnit;
     private final int quantity;
 
@@ -96,7 +98,7 @@ public static LargeTextFactory defaultFactory()
 
     private LargeTextFactory(final Builder builder)
     {
-        charset = builder.charset;
+        decoderSupplier = builder.decoderSupplier;
         sizeUnit = builder.sizeUnit;
         quantity = builder.quantity;
     }
@@ -121,7 +123,7 @@ public LargeText fromPath(@Nonnull final Path path)
         Preconditions.checkNotNull(path, "path must not be null");
         final FileChannel channel = FileChannel.open(path,
             StandardOpenOption.READ);
-        return new NotThreadSafeLargeText(channel, charset, quantity, sizeUnit);
+        return new NotThreadSafeLargeText(channel, decoderSupplier, quantity, sizeUnit);
     }
 
     /**
@@ -141,7 +143,7 @@ public LargeText load(@Nonnull final Path path)
         Preconditions.checkNotNull(path, "path must not be null");
         final FileChannel channel = FileChannel.open(path,
             StandardOpenOption.READ);
-        return new NotThreadSafeLargeText(channel, charset, quantity, sizeUnit);
+        return new NotThreadSafeLargeText(channel, decoderSupplier, quantity, sizeUnit);
     }
 
     /**
@@ -160,7 +162,7 @@ public LargeText loadThreadSafe(@Nonnull final Path path)
         Preconditions.checkNotNull(path, "path must not be null");
         final FileChannel channel = FileChannel.open(path,
             StandardOpenOption.READ);
-        return new ThreadSafeLargeText(channel, charset, quantity, sizeUnit);
+        return new ThreadSafeLargeText(channel, decoderSupplier, quantity, sizeUnit);
     }
 
     /**
@@ -172,7 +174,8 @@ public static final class Builder
         private static final long MIN_WINDOW_SIZE = 1024L;
         private static final long MAX_WINDOW_SIZE = (long) Integer.MAX_VALUE;
 
-        private Charset charset = StandardCharsets.UTF_8;
+        private Supplier<CharsetDecoder> decoderSupplier =
+                defaultDecoder(StandardCharsets.UTF_8);
         private SizeUnit sizeUnit = SizeUnit.MiB;
         private int quantity = 2;
 
@@ -189,8 +192,9 @@ private Builder()
          */
         public Builder setCharset(@Nonnull final Charset charset)
         {
-            this.charset = Preconditions.checkNotNull(charset,
-                "charset cannot be null");
+            this.decoderSupplier = defaultDecoder(Preconditions.checkNotNull(
+                    charset, "charset cannot be null"
+            ));
             return this;
         }
 
@@ -210,6 +214,13 @@ public Builder setCharsetByName(@Nonnull final String charsetByName)
             return setCharset(c);
         }
 
+        public Builder setCharsetDecoder(@Nonnull final Supplier<CharsetDecoder> supplier)
+        {
+            this.decoderSupplier = Preconditions.checkNotNull(supplier,
+                    "charset decoder supplier cannot be null");
+            return this;
+        }
+
         /**
          * Set the window size for this factory
          *
@@ -248,4 +259,16 @@ public LargeTextFactory build()
             return new LargeTextFactory(this);
         }
     }
+
+    private static Supplier<CharsetDecoder> defaultDecoder(@Nonnull final Charset charset)
+    {
+        return new Supplier<CharsetDecoder>()
+        {
+            @Override
+            public CharsetDecoder get()
+            {
+                return charset.newDecoder();
+            }
+        };
+    }
 }
diff --git a/src/main/java/com/github/fge/largetext/NotThreadSafeLargeText.java b/src/main/java/com/github/fge/largetext/NotThreadSafeLargeText.java
index 4df328d..857eb7f 100644
--- a/src/main/java/com/github/fge/largetext/NotThreadSafeLargeText.java
+++ b/src/main/java/com/github/fge/largetext/NotThreadSafeLargeText.java
@@ -20,13 +20,14 @@
 
 import com.github.fge.largetext.load.TextRange;
 import com.github.fge.largetext.range.IntRange;
+import com.google.common.base.Supplier;
 
 import javax.annotation.ParametersAreNonnullByDefault;
 import javax.annotation.concurrent.NotThreadSafe;
 import java.io.IOException;
 import java.nio.CharBuffer;
 import java.nio.channels.FileChannel;
-import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
 import java.nio.file.Path;
 
 /**
@@ -48,11 +49,11 @@ public final class NotThreadSafeLargeText
     private IntRange range = EMPTY_RANGE;
     private CharBuffer buffer = EMPTY_BUFFER;
 
-    NotThreadSafeLargeText(final FileChannel channel, final Charset charset,
+    NotThreadSafeLargeText(final FileChannel channel, final Supplier<CharsetDecoder> decoderSupplier,
         final int quantity, final SizeUnit sizeUnit)
         throws IOException
     {
-        super(channel, charset, quantity, sizeUnit);
+        super(channel, decoderSupplier, quantity, sizeUnit);
     }
 
     @Override
diff --git a/src/main/java/com/github/fge/largetext/ThreadSafeLargeText.java b/src/main/java/com/github/fge/largetext/ThreadSafeLargeText.java
index 6bd3002..2e9f1fe 100644
--- a/src/main/java/com/github/fge/largetext/ThreadSafeLargeText.java
+++ b/src/main/java/com/github/fge/largetext/ThreadSafeLargeText.java
@@ -20,13 +20,14 @@
 
 import com.github.fge.largetext.load.TextRange;
 import com.github.fge.largetext.range.IntRange;
+import com.google.common.base.Supplier;
 
 import javax.annotation.ParametersAreNonnullByDefault;
 import javax.annotation.concurrent.ThreadSafe;
 import java.io.IOException;
 import java.nio.CharBuffer;
 import java.nio.channels.FileChannel;
-import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
 import java.nio.file.Path;
 
 /**
@@ -59,11 +60,11 @@ protected CurrentBuffer initialValue()
             }
         };
 
-    ThreadSafeLargeText(final FileChannel channel, final Charset charset,
+    ThreadSafeLargeText(final FileChannel channel, final Supplier<CharsetDecoder> decoderSupplier,
         final int quantity, final SizeUnit sizeUnit)
         throws IOException
     {
-        super(channel, charset, quantity, sizeUnit);
+        super(channel, decoderSupplier, quantity, sizeUnit);
     }
 
     @Override
diff --git a/src/main/java/com/github/fge/largetext/load/TextCache.java b/src/main/java/com/github/fge/largetext/load/TextCache.java
index d4f53c3..b1aa5aa 100644
--- a/src/main/java/com/github/fge/largetext/load/TextCache.java
+++ b/src/main/java/com/github/fge/largetext/load/TextCache.java
@@ -20,6 +20,7 @@
 
 import com.github.fge.largetext.LargeTextException;
 import com.github.fge.largetext.range.LongRange;
+import com.google.common.base.Supplier;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.LoadingCache;
@@ -30,7 +31,6 @@
 import java.nio.CharBuffer;
 import java.nio.MappedByteBuffer;
 import java.nio.channels.FileChannel;
-import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
 import java.util.Map;
 import java.util.concurrent.ExecutionException;
@@ -54,7 +54,7 @@
 public final class TextCache
 {
     private final FileChannel channel;
-    private final Charset charset;
+    private final Supplier<CharsetDecoder> decoderSupplier;
 
     /*
      * This is why we need Guava: we want cache expiry, and it has this builtin.
@@ -63,10 +63,10 @@ public final class TextCache
      */
     private final LoadingCache<TextRange, CharBuffer> cache;
 
-    public TextCache(final FileChannel channel, final Charset charset)
+    public TextCache(final FileChannel channel, final Supplier<CharsetDecoder> decoderSupplier)
     {
         this.channel = channel;
-        this.charset = charset;
+        this.decoderSupplier = decoderSupplier;
         cache = CacheBuilder.<TextRange, CharBuffer>newBuilder()
             .expireAfterAccess(30L, TimeUnit.SECONDS)
             .recordStats().build(loader());
@@ -120,7 +120,7 @@ public CharBuffer load(@Nonnull final TextRange key)
                 final long size = byteRange.getUpperBound() - start;
                 final MappedByteBuffer buffer = channel.map(MapMode.READ_ONLY,
                     start, size);
-                final CharsetDecoder decoder = charset.newDecoder();
+                final CharsetDecoder decoder = decoderSupplier.get();
                 return decoder.decode(buffer).asReadOnlyBuffer();
             }
         };
diff --git a/src/main/java/com/github/fge/largetext/load/TextDecoder.java b/src/main/java/com/github/fge/largetext/load/TextDecoder.java
index b31b806..294d13b 100644
--- a/src/main/java/com/github/fge/largetext/load/TextDecoder.java
+++ b/src/main/java/com/github/fge/largetext/load/TextDecoder.java
@@ -22,6 +22,7 @@
 import com.github.fge.largetext.LargeTextException;
 import com.github.fge.largetext.LargeTextFactory;
 import com.github.fge.largetext.range.IntRange;
+import com.google.common.base.Supplier;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.RangeMap;
 import com.google.common.collect.TreeRangeMap;
@@ -34,11 +35,8 @@
 import java.nio.CharBuffer;
 import java.nio.MappedByteBuffer;
 import java.nio.channels.FileChannel;
-import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
 import java.nio.charset.CoderResult;
-import java.nio.charset.CodingErrorAction;
-import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -87,7 +85,7 @@ public final class TextDecoder
     private final RangeMap<Integer, TextRange> ranges = TreeRangeMap.create();
 
     private final FileChannel channel;
-    private final Charset charset;
+    private final Supplier<CharsetDecoder> decoderSupplier;
     private final long fileSize;
     private final long targetMapSize;
 
@@ -95,18 +93,18 @@ public final class TextDecoder
      * Constructor; don't use directly!
      *
      * @param channel the {@link FileChannel} to the target file
-     * @param charset the character encoding to use
+     * @param decoderSupplier the character decoder to use
      * @param targetMapSize the target byte mapping size
      * @throws IOException error obtaining information on the channel
      */
-    public TextDecoder(final FileChannel channel, final Charset charset,
+    public TextDecoder(final FileChannel channel, final Supplier<CharsetDecoder> decoderSupplier,
         final long targetMapSize)
         throws IOException
     {
         this.channel = channel;
         fileSize = channel.size();
         this.targetMapSize = targetMapSize;
-        this.charset = charset;
+        this.decoderSupplier = decoderSupplier;
         executor.submit(decodingTask());
     }
 
@@ -151,12 +149,11 @@ public List<TextRange> getRanges(final IntRange range)
             Thread.currentThread().interrupt();
             throw new LargeTextException("Interrupted", e);
         }
-        final Collection<TextRange> ret;
         synchronized (ranges) {
-            ret = ranges.subRangeMap(range.asGuavaRange())
-                .asMapOfRanges().values();
+            return ImmutableList.copyOf(
+                    ranges.subRangeMap(range.asGuavaRange()).asMapOfRanges().values()
+            );
         }
-        return ImmutableList.copyOf(ret);
     }
 
     /**
@@ -199,9 +196,7 @@ private Runnable decodingTask()
             @Override
             public void run()
             {
-                final CharsetDecoder decoder = charset.newDecoder()
-                    .onMalformedInput(CodingErrorAction.REPORT)
-                    .onUnmappableCharacter(CodingErrorAction.REPORT);
+                final CharsetDecoder decoder = decoderSupplier.get();
                 final CharBuffer charMap
                     = CharBuffer.allocate((int) targetMapSize);
 
@@ -228,11 +223,11 @@ public void run()
                     }
                     byteOffset = textRange.getByteRange().getUpperBound();
                     charOffset = textRange.getCharRange().getUpperBound();
-                    status.setNrChars(charOffset);
                     synchronized (ranges) {
                         ranges.put(textRange.getCharRange().asGuavaRange(),
                             textRange);
                     }
+                    status.setNrChars(charOffset);
                 }
                 status.setFinished(charOffset);
             }
@@ -244,7 +239,13 @@ private TextRange nextRange(final long byteOffset, final int charOffset,
         final CharsetDecoder decoder, final CharBuffer charMap)
         throws IOException
     {
-        long nrBytes = Math.min(targetMapSize, fileSize - byteOffset);
+        long nrBytes = fileSize - byteOffset;
+        boolean endOfInput = true;
+
+        if (nrBytes > targetMapSize) {
+            nrBytes = targetMapSize;
+            endOfInput = false;
+        }
 
         final MappedByteBuffer byteMap
             = channel.map(FileChannel.MapMode.READ_ONLY, byteOffset, nrBytes);
@@ -252,7 +253,7 @@ private TextRange nextRange(final long byteOffset, final int charOffset,
         charMap.rewind();
         decoder.reset();
 
-        final CoderResult result = decoder.decode(byteMap, charMap, true);
+        final CoderResult result = decoder.decode(byteMap, charMap, endOfInput);
 
         /*
          * Unmappable character... It _can_ happen even with a decoder, see
@@ -265,8 +266,8 @@ private TextRange nextRange(final long byteOffset, final int charOffset,
          * Incomplete byte sequence: in this case, the mapping position reflects
          * what was actually read; change the mapping size
          */
-        if (result.isMalformed())
-            nrBytes = (long) byteMap.position();
+        if (result.isUnderflow() || result.isMalformed())
+            nrBytes = byteMap.position();
 
         return new TextRange(byteOffset, nrBytes, charOffset,
             charMap.position());
diff --git a/src/main/java/com/github/fge/largetext/sequence/EmptyCharSequence.java b/src/main/java/com/github/fge/largetext/sequence/EmptyCharSequence.java
index 176e36f..f388ea4 100644
--- a/src/main/java/com/github/fge/largetext/sequence/EmptyCharSequence.java
+++ b/src/main/java/com/github/fge/largetext/sequence/EmptyCharSequence.java
@@ -51,4 +51,8 @@ public CharSequence subSequence(final int start, final int end)
         return this;
     }
 
+    @Override
+    public String toString() {
+        return "";
+    }
 }
diff --git a/src/test/java/com/github/fge/largetext/NotThreadSafeLargeTextTest.java b/src/test/java/com/github/fge/largetext/NotThreadSafeLargeTextTest.java
index 44cfe0d..610fb6b 100644
--- a/src/test/java/com/github/fge/largetext/NotThreadSafeLargeTextTest.java
+++ b/src/test/java/com/github/fge/largetext/NotThreadSafeLargeTextTest.java
@@ -19,6 +19,9 @@
 package com.github.fge.largetext;
 
 import com.google.common.base.Strings;
+import com.google.common.base.Supplier;
+import org.apache.commons.lang3.RandomStringUtils;
+import org.assertj.core.api.ThrowableAssert;
 import org.testng.annotations.AfterClass;
 import org.testng.annotations.BeforeClass;
 import org.testng.annotations.DataProvider;
@@ -27,30 +30,62 @@
 import java.io.BufferedWriter;
 import java.io.IOException;
 import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.CodingErrorAction;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Random;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 public final class NotThreadSafeLargeTextTest
 {
-    private final String testString = Strings.repeat("abcdefghij", 5000);
-    private final int len = testString.length();
+    private static final SizeUnit windowSizeUnit = SizeUnit.KiB;
+    private static final int windowSize = 16;
+    // safe to cast as max window size supported by LargeText is Integer.MAX_VALUE
+    private static final int len = (int) windowSizeUnit.sizeInBytes(windowSize);
+    private static final Charset charset = StandardCharsets.UTF_8;
+    private static final LargeTextFactory defaultFactory;
+    private static final LargeTextFactory replaceFactory;
+    private static final LargeTextFactory ignoreFactory;
+    private final String testString = RandomStringUtils.random(len);
     private final Random random = new Random(System.nanoTime());
 
+    static {
+        final LargeTextFactory.Builder builder = LargeTextFactory.newBuilder()
+                .setWindowSize(windowSize, windowSizeUnit);
+
+        defaultFactory = builder.setCharset(charset).build();
+        replaceFactory = builder.setCharsetDecoder(new Supplier<CharsetDecoder>()
+        {
+            @Override
+            public CharsetDecoder get()
+            {
+                return StandardCharsets.UTF_8.newDecoder().onMalformedInput(CodingErrorAction.REPLACE);
+            }
+        }).build();
+        ignoreFactory = builder.setCharsetDecoder(new Supplier<CharsetDecoder>()
+        {
+            @Override
+            public CharsetDecoder get()
+            {
+                return StandardCharsets.UTF_8.newDecoder().onMalformedInput(CodingErrorAction.IGNORE);
+            }
+        }).build();
+    }
+
     private Path testFile;
-    private LargeText largeText;
 
     @BeforeClass
     public void createFile()
         throws IOException
     {
-        final Charset charset = StandardCharsets.UTF_8;
         testFile = Files.createTempFile("foo", "bar");
         try (
             final BufferedWriter writer = Files.newBufferedWriter(testFile,
@@ -59,42 +94,172 @@ public void createFile()
             writer.write(testString);
             writer.flush();
         }
-
-        final LargeTextFactory factory = LargeTextFactory.newBuilder()
-            .setWindowSize(16, SizeUnit.KiB)
-            .build();
-        largeText = factory.load(testFile);
     }
 
     @DataProvider
-    public Iterator<Object[]> getIndices()
+    public Iterator<Object[]> getFactoriesAndIndices()
     {
         final List<Object[]> list = new ArrayList<>();
 
-        for (int i = 0; i < 200; i++)
-            list.add(new Object[] { random.nextInt(len) });
+        for (final LargeTextFactory factory : Arrays.asList(defaultFactory, replaceFactory, ignoreFactory))
+            for (int i = 0; i < 2_000; i++)
+                list.add(new Object[] { factory, random.nextInt(len) });
 
         return list.iterator();
     }
 
+    @Test(dataProvider = "getFactoriesAndIndices")
+    public void nonThreadSafeLargeTextWorks(final LargeTextFactory factory, final int index)
+            throws IOException
+    {
+        try (LargeText text = factory.load(testFile)) {
+            final char actual = text.charAt(index);
+            final char expected = text.charAt(index);
+            assertThat(actual).overridingErrorMessage(
+                    "Wrong character picked up! Was '%s', expected '%s'",
+                    actual, expected
+            ).isEqualTo(expected);
+        }
+    }
+
+    @Test
+    public void reportsMalformedCharacterByDefault()
+            throws IOException
+    {
+        try (final TemporaryFile tmp = new TemporaryFile()) {
+            final Path path = tmp.getPath();
+            Files.write(path, new byte[]{
+                    (byte) 0x48,  // H
+                    (byte) 0x65,  // e
+                    (byte) 0x6C,  // l
+                    (byte) 0xD0,  // ???
+                    (byte) 0x6F   // o
+            });
+
+            try (final LargeText text = defaultFactory.load(path)) {
+                assertThatThrownBy(new ThrowableAssert.ThrowingCallable()
+                {
+                    @Override
+                    public void call()
+                    {
+                        text.charAt(4);
+                    }
+                }).isInstanceOf(LargeTextException.class).hasMessage("decoding error");
+            }
+        }
+    }
+
+    @Test
+    public void replacesMalformedCharacterWhenDecoderIsConfiguredToReplace()
+            throws IOException
+    {
+        try (final TemporaryFile tmp = new TemporaryFile()) {
+            final Path path = tmp.getPath();
+            Files.write(path, new byte[]{
+                    (byte) 0x48,  // H
+                    (byte) 0x65,  // e
+                    (byte) 0x6C,  // l
+                    (byte) 0xD0,  // ???
+                    (byte) 0x6F   // o
+            });
+
+            try (final LargeText text = replaceFactory.load(path)) {
+                assertThat(text.charAt(3)).isEqualTo('�');
+                assertThat(text.charAt(4)).isEqualTo('o');
+                assertThat(text.toString()).isEqualTo("Hel�o");
+            }
+        }
+    }
+
+    @Test
+    public void replacesMalformedCharacterOnUpperBoundWhenDecoderIsConfiguredToReplace()
+            throws IOException
+    {
+        int size = (int) windowSizeUnit.sizeInBytes(windowSize);
+        final byte[] content = new byte[size + 2];
+        Arrays.fill(content, (byte) 0x61);  // a
+        content[size] = (byte) 0xD0;  // ???
+
+        try (final TemporaryFile tmp = new TemporaryFile()) {
+            final Path path = tmp.getPath();
+            Files.write(path, content);
+
+            try (final LargeText text = replaceFactory.load(path)) {
+                assertThat(text.charAt(size - 1)).isEqualTo('a');
+                assertThat(text.charAt(size)).isEqualTo('�');
+                assertThat(text.charAt(size + 1)).isEqualTo('a');
+            }
+        }
+    }
+
+    @Test
+    public void ignoresMalformedCharacterWhenDecoderIsConfiguredToIgnore()
+            throws IOException
+    {
+        try (final TemporaryFile tmp = new TemporaryFile()) {
+            final Path path = tmp.getPath();
+            Files.write(path, new byte[]{
+                    (byte) 0x48,  // H
+                    (byte) 0x65,  // e
+                    (byte) 0x6C,  // l
+                    (byte) 0xD0,  // ???
+                    (byte) 0x6F   // o
+            });
+
+            try (final LargeText text = ignoreFactory.load(path)) {
+                assertThat(text.charAt(3)).isEqualTo('o');
+                assertThat(text.toString()).isEqualTo("Helo");
+            }
+        }
+    }
 
-    @Test(dataProvider = "getIndices")
-    public void nonThreadSafeLargeTextWorks(final int index)
+    // Bug was found when NotThreadSafeLargeTextTest was updated to use multiple LargeTexts
+    // instead of single created in set up method.
+    //
+    // Issue is: status.setNrChars(charOffset) unblocks thread that awaits for character but
+    // at the same time it does not guarantee that TextRange will be put to ranges map.
+    // NullPointerException happens in this order:
+    //
+    // 1. main thread invokes charAt with index that is not yet available
+    // 2. text decoder in main thread adds CharWaiter and blocks in await()
+    // 3. text-decoder thread travels through file until it reaches window that
+    //    includes requested index
+    // 4. status.setNrChars(charOffset) at TextDecoder:226 unblocks main
+    //    main thread as required index is reached
+    // 5. main thread wins race and synchronizes on ranges to get range. Range is not
+    //    written yet, method returns null, NullPointerException is generated at
+    //    NotThreadSafeLargeText:64
+    // 6. text-decoder thread synchronizes on ranges and writes range.
+    //
+    // Set breakpoints (one that suspend single thread, not all threads) at:
+    // * TextDecoder:130 (synchronization on ranges)
+    // * TextDecoder:227 (synchronization on ranges)
+    //
+    // To reproduce, execute this test in debug mode.
+    //
+    // * if breakpoint hits text-decoder thread - switch to main and step over
+    // * if breakpoint hits main thread - step over
+    @Test
+    public void reproduceCharAtNullPointerExceptionCausedByStatusReportedBeforeRangesUpdate()
+        throws IOException
     {
-        final char actual = largeText.charAt(index);
-        final char expected = testString.charAt(index);
-        assertThat(actual).overridingErrorMessage(
-            "Wrong character picked up! Was '%s', expected '%s'",
-            actual, expected
-        ).isEqualTo(expected);
+        final String string = Strings.repeat("abcde", 5_000);
+        try (final TemporaryFile tmp = new TemporaryFile()) {
+            final Path path = tmp.getPath();
+
+            Files.write(path, string.getBytes(StandardCharsets.UTF_8));
+
+            try (final  LargeText text = LargeTextFactory.defaultFactory().load(path)) {
+                text.charAt(500);
+            }
+        }
     }
 
     @AfterClass
-    public void closeEverything()
+    public void deleteFile()
         throws IOException
     {
-        largeText.close();
         Files.delete(testFile);
     }
 
-}
\ No newline at end of file
+}
diff --git a/src/test/java/com/github/fge/largetext/TemporaryFile.java b/src/test/java/com/github/fge/largetext/TemporaryFile.java
new file mode 100644
index 0000000..f4e1746
--- /dev/null
+++ b/src/test/java/com/github/fge/largetext/TemporaryFile.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2014, Francis Galiegue (fgaliegue@gmail.com)
+ *
+ * This software is dual-licensed under:
+ *
+ * - the Lesser General Public License (LGPL) version 3.0 or, at your option, any
+ *   later version;
+ * - the Apache Software License (ASL) version 2.0.
+ *
+ * The text of both licenses is available under the src/resources/ directory of
+ * this project (under the names LGPL-3.0.txt and ASL-2.0.txt respectively).
+ *
+ * Direct link to the sources:
+ *
+ * - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt
+ * - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
+ */
+
+package com.github.fge.largetext;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.FileAttribute;
+
+/**
+ * Thin wrapper of {@link Files#createTempFile(String, String, FileAttribute[])} that
+ * removes temporary file on {@link #close()}.
+ */
+public final class TemporaryFile implements AutoCloseable
+{
+    private final Path path;
+
+    /**
+     * @throws IOException if fails to create temporary file
+     */
+    public TemporaryFile()
+            throws IOException
+    {
+        this(null, null);
+    }
+
+    /**
+     * @param prefix the prefix string to be used in generated file's name
+     * @param suffix the suffix string to be used in generated file's name
+     * @throws IOException if fails to create temporary file
+     */
+    public TemporaryFile(String suffix, String prefix)
+            throws IOException
+    {
+        this.path = Files.createTempFile(suffix, prefix);
+    }
+
+    public Path getPath()
+    {
+        return path;
+    }
+
+    @Override
+    public void close()
+            throws IOException
+    {
+        Files.delete(path);
+    }
+}
diff --git a/src/test/java/com/github/fge/largetext/ThreadSafeLargeTextTest.java b/src/test/java/com/github/fge/largetext/ThreadSafeLargeTextTest.java
index d45b459..c28493e 100644
--- a/src/test/java/com/github/fge/largetext/ThreadSafeLargeTextTest.java
+++ b/src/test/java/com/github/fge/largetext/ThreadSafeLargeTextTest.java
@@ -18,7 +18,7 @@
 
 package com.github.fge.largetext;
 
-import com.google.common.base.Strings;
+import org.apache.commons.lang3.RandomStringUtils;
 import org.testng.annotations.AfterClass;
 import org.testng.annotations.BeforeClass;
 import org.testng.annotations.Test;
@@ -35,7 +35,7 @@
 
 public final class ThreadSafeLargeTextTest
 {
-    private final String testString = Strings.repeat("abcdefghij", 5000);
+    private final String testString = RandomStringUtils.random(5_000);
     private final int len = testString.length();
     private final Random random = new Random(System.nanoTime());
 
@@ -81,4 +81,4 @@ public void closeEverything()
         largeText.close();
         Files.delete(testFile);
     }
-}
\ No newline at end of file
+}
diff --git a/src/test/java/com/github/fge/largetext/load/TextDecoderTest.java b/src/test/java/com/github/fge/largetext/load/TextDecoderTest.java
new file mode 100644
index 0000000..0bf1c67
--- /dev/null
+++ b/src/test/java/com/github/fge/largetext/load/TextDecoderTest.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2014, Francis Galiegue (fgaliegue@gmail.com)
+ *
+ * This software is dual-licensed under:
+ *
+ * - the Lesser General Public License (LGPL) version 3.0 or, at your option, any
+ *   later version;
+ * - the Apache Software License (ASL) version 2.0.
+ *
+ * The text of both licenses is available under the src/resources/ directory of
+ * this project (under the names LGPL-3.0.txt and ASL-2.0.txt respectively).
+ *
+ * Direct link to the sources:
+ *
+ * - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt
+ * - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
+ */
+
+package com.github.fge.largetext.load;
+
+import com.github.fge.largetext.LargeText;
+import com.github.fge.largetext.LargeTextFactory;
+import com.github.fge.largetext.SizeUnit;
+import com.github.fge.largetext.TemporaryFile;
+import com.google.common.base.Strings;
+import org.testng.annotations.Test;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class TextDecoderTest
+{
+    // ConcurrentModificationException is thrown when view of ranges is
+    // copied to ImmutableList and decoding task hasn't finished yet (
+    // writes to ranges map).
+    //
+    // It is hard to reproduce ConcurrentModificationException without
+    // modification of TextDecoder. It is doable in debug mode.
+    //
+    // Set breakpoints (one that suspend single thread, not all threads) at:
+    // * TreeMap:1696 (SubMapIterator#nextEntry start)
+    // * TextDecoder:233 (synchronized block in decodingTask)
+    //
+    // Execute this test in debug mode.
+    //
+    // * resume until breakpoint in nextEntry becomes available
+    //   (usually takes a hit or two)
+    // * switch to "text-decoder" thread
+    // * step through synchronized block
+    // * switch back to nextEntry thread
+    // * step through until m.modCount != expectedModCount because put
+    //   happened
+    @Test
+    public void reproduceGetRangesConcurrentModificationException()
+            throws IOException
+    {
+        final String string = Strings.repeat("abcde", 5_000);
+        try (final TemporaryFile tmp = new TemporaryFile()) {
+            final Path path = tmp.getPath();
+
+            Files.write(path, string.getBytes(StandardCharsets.UTF_8));
+
+            final LargeTextFactory factory = LargeTextFactory.newBuilder()
+                    .setCharset(StandardCharsets.US_ASCII)
+                    .setWindowSize(1024, SizeUnit.B)
+                    .build();
+
+            try (final LargeText text = factory.load(path)) {
+                text.subSequence(0, 450);
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/github/fge/largetext/sequence/EmptyCharSequenceTest.java b/src/test/java/com/github/fge/largetext/sequence/EmptyCharSequenceTest.java
new file mode 100644
index 0000000..ffe798d
--- /dev/null
+++ b/src/test/java/com/github/fge/largetext/sequence/EmptyCharSequenceTest.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2014, Francis Galiegue (fgaliegue@gmail.com)
+ *
+ * This software is dual-licensed under:
+ *
+ * - the Lesser General Public License (LGPL) version 3.0 or, at your option, any
+ *   later version;
+ * - the Apache Software License (ASL) version 2.0.
+ *
+ * The text of both licenses is available under the src/resources/ directory of
+ * this project (under the names LGPL-3.0.txt and ASL-2.0.txt respectively).
+ *
+ * Direct link to the sources:
+ *
+ * - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt
+ * - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
+ */
+
+package com.github.fge.largetext.sequence;
+
+import org.testng.annotations.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class EmptyCharSequenceTest
+{
+    @Test
+    public void toStringReturnsEmptyString() {
+        assertThat(EmptyCharSequence.INSTANCE.toString()).isEmpty();
+    }
+}
diff --git a/src/test/java/com/github/fge/largetext/sequence/TextRangeCharSequenceTest.java b/src/test/java/com/github/fge/largetext/sequence/TextRangeCharSequenceTest.java
index 254f301..fa43a9e 100644
--- a/src/test/java/com/github/fge/largetext/sequence/TextRangeCharSequenceTest.java
+++ b/src/test/java/com/github/fge/largetext/sequence/TextRangeCharSequenceTest.java
@@ -21,8 +21,9 @@
 import com.github.fge.largetext.load.TextCache;
 import com.github.fge.largetext.load.TextDecoder;
 import com.github.fge.largetext.range.IntRange;
-import com.google.common.base.Strings;
+import com.google.common.base.Supplier;
 import com.google.common.collect.Lists;
+import org.apache.commons.lang3.RandomStringUtils;
 import org.testng.annotations.AfterClass;
 import org.testng.annotations.BeforeClass;
 import org.testng.annotations.DataProvider;
@@ -33,6 +34,7 @@
 import java.nio.CharBuffer;
 import java.nio.channels.FileChannel;
 import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -48,13 +50,21 @@ public final class TextRangeCharSequenceTest
     private Path testFile;
     private FileChannel channel;
     private CharSequenceFactory factory;
-    private final String testString = Strings.repeat("abcdefghij", 5000);
+    private final String testString = RandomStringUtils.random(5_000);
 
     @BeforeClass
     public void createFile()
         throws IOException
     {
         final Charset charset = StandardCharsets.UTF_8;
+        final Supplier<CharsetDecoder> decoderSupplier = new Supplier<CharsetDecoder>()
+        {
+            @Override
+            public CharsetDecoder get()
+            {
+                return charset.newDecoder();
+            }
+        };
         testFile = Files.createTempFile("foo", "bar");
         try (
             final BufferedWriter writer = Files.newBufferedWriter(testFile,
@@ -64,8 +74,8 @@ public void createFile()
             writer.flush();
         }
         channel = FileChannel.open(testFile, StandardOpenOption.READ);
-        final TextDecoder decoder = new TextDecoder(channel, charset, 1000L);
-        final TextCache loader = new TextCache(channel, charset);
+        final TextDecoder decoder = new TextDecoder(channel, decoderSupplier, 1000L);
+        final TextCache loader = new TextCache(channel, decoderSupplier);
         factory = new CharSequenceFactory(decoder, loader);
     }
 
@@ -74,7 +84,7 @@ public Iterator<Object[]> getClassTests()
     {
         final List<Object[]> list = Lists.newArrayList();
 
-        list.add(new Object[] { 0, 1000, CharBuffer.class });
+        list.add(new Object[] { 0, 250 /* 1000 / max 4 bytes per character */, CharBuffer.class });
         list.add(new Object[] { 500, 1049, MultiRangeCharSequence.class });
 
         return list.iterator();