To add a JRE, the class file must be located in lib/java_buildpack/jre and the class name added to config/components.yml. The class must have the following methods:
# An initializer for the instance.
#
# @param [Hash<Symbol, String>] context A shared context provided to all components
# @option context [String] :app_dir the directory that the application exists in
# @option context [Hash] :environment A hash containing all environment variables except +VCAP_APPLICATION+ and
# +VCAP_SERVICES+. Those values are available separately in parsed form.
# @option context [String] :java_home the directory that acts as +JAVA_HOME+
# @option context [Array<String>] :java_opts an array that Java options can be added to
# @option context [String] :lib_directory the directory that additional libraries are placed in
# @option context [Hash] :vcap_application The contents of the +VCAP_APPLICATION+ environment variable
# @option context [Hash] :vcap_services The contents of the +VCAP_SERVICES+ environment variable
# @option context [Hash] :configuration the configuration provided by the user
def initialize(context)
# Determines if the JRE can be used to run the application.
#
# @return [Array<String>, String, nil] If the JRE can be used to run the application, a +String+ or an +Array<String>+
# that uniquely identifies the JRE (e.g. +openjdk-1.7.0_21+). Otherwise, +nil+.
def detect
# Downloads and unpacks the JRE. Status output written to +STDOUT+ is expected as part of this invocation.
#
# @return [void]
def compile
# Adds any JRE-specific options to +context[:java_opts]+. Typically this includes memory configuration (heap, perm gen,
# etc.) but could be anything that a JRE needs to have configured. As well, +context[:java_home]+ is expected to be
# updated with the value that the JRE has been unpacked to. This must be done using the {String.concat} method to
# ensure that the value is accessible to other components.
#
# @return [void]
def release