Replace token in file before building, but keep token in sources

Question

I want to replace a @VERSION@ token in a java source file with a version before building (Gradle is my build system of choice).

In my current script a

Answer 1

To complement other answers, I found this idiom more simple if there's only one value you are looking to change:

task generateSources(type: Copy) {
    from 'src/main/java'
    into 'build/src/main/java'
    filter { line -> line.replaceAll('xxx', 'aaa') }
}