bridger

A bytecode mangler for creating your own synthetic bridge methods, which allows more dramatic source code changes while still maintaining binary compatibility. And probably some other ugly tricks too.

Usage: Source code

In your Java source, create your bridge methods with $$bridge in the name. Everything before the $$bridge is retained, everything including and after it is discarded. The methods will additionally be tagged as ACC_BRIDGE and ACC_SYNTHETIC.

If the bridge method name includes $$public after $$bridge, the bridge method will additionally be made public in the bytecode. Similarly, $$protected can be used to make the bridge method protected. This allows keeping the bridge method private in the source code. (If neither $$public nor $$protected is present in the name, the access mode of the method is left unchanged.)

If you add the @hidden tag (available since Java 9) to the method's JavaDoc comment, it will not show up in rendered documentation for the class.

Usage: Maven

Add a snippet like this to your pom.xml:

<build>
    <plugins>
        <plugin>
            <groupId>org.jboss.bridger</groupId>
            <artifactId>bridger</artifactId>
            <version>1.6.Final</version>
            <executions>
                <!-- run after "compile", runs bridger on main classes -->
                <execution>
                    <id>weave</id>
                    <phase>process-classes</phase>
                    <goals>
                        <goal>transform</goal>
                    </goals>
                </execution>
                <!-- run after "test-compile", runs bridger on test classes -->
                <execution>
                    <id>weave-tests</id>
                    <phase>process-test-classes</phase>
                    <goals>
                        <goal>transform</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${project.build.testOutputDirectory}</outputDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

Note that a separate execution is needed if you want your test classes to be transformed.

Usage: Command Line

Execute like this:

java -classpath path/to/bridger.jar:path/to/asm-6.0.jar org.jboss.bridger.Bridger path/of/class/files/

You can also perform single method transforms on any given method like this:

java -classpath path/to/bridger.jar:path/to/asm-6.0.jar org.jboss.bridger.Bridger --single-transform path/to/class/file.class methodName [methodDescriptor]

Using this mechanism, the method does not need to have $$bridge in the name. This bridges all overloads of the method with this name, unless the descriptor is provided. Note that this uses JVM method descriptor notation, so a method such as void method(String s, int i) would have the descriptor (Ljava/lang/String;I)V. This can be obtained by for instance using javap -s on the class file.

The class files will be transformed in place.