GWT Exclude Package From Source Path

Problem

The Google Web Toolkit Java to JavaScript transpiler is a powerful tool to convert Java source code into JavaScript files. Unfortunately, not all Java code can be transpiled into JavaScript code by GWT.

Sometimes, a project contains a mix of Java code that can be converted into JavaScript and Java code that doesn’t. In that case, the GWT compiler issues errors such as ‘No source code is available for type …‘.

Solution

GWT module definitions (.gwt.xml) files allow to specify fine-grained rules which files in a project are to be converted and which files should not. The rules are based on Ant patterns, which can be difficult to wrap one’s head around. Below are a few handy examples.

Exclude all files in packages with the name ‘/jre/’

<source path='' >

    <exclude name="**/jre/**" />
</source>

Exclude the file ‘ForJre.java’:

<source path='' >
   <exclude name="**/ForJre.java" />
</source>