This proof-of-concept project aims to make a binary port of a Java 8 API to an earlier Java major versions. The experiment is based on a simple Java 8 Stream API example supposed to run on Java 6:

Stream.of(args).map(String::toUpperCase).forEach(EntryPoint::dump)

Requirements:

• JDK 1.8
• Ant 1.9.7
• JDK or JRE 1.6 to run the ported code

How to build

To build the project, use the following command:

ant clean all

or alternatively:

./build.sh

How to run

Once the target artifacts are built, the target artifacts (both downgraded JDK 8 classes and the test classes) can be ran on different JVMs.

To run the example on Java 8, make sure you have the environment variable JDK_8_HOME variable set to your Java 8 home. To run the example on Java 6, make sure you have JDK_6_HOME set. Once the variables exist, run:

ant run-as-java-8

or alternatively:

./run-java-8.sh

If the command above succeeds, then the Java 6-targeted exampled can be launched:

ant run-as-java-6

or alternatively:

./run-java-6.sh

Results

The result programmatic output of both run-as-java-6 and run-as-java-8 is expected to be the same:

pre: stream
>FOO
>BAR
>BAZ
post: stream