// Assume you have an interface 'Transformer' in your classpath
// in src/main/java.  It has a single method 'Object transform(Object)'.
// Further assume that 'MatrixTransformer' is an implementation of
// Transformer in src/test/java.

// Create a compiler instance which acts as a factory for
// ProxyClass objects.
ProxyCompiler compiler = new KJavacCompiler();
compiler.setClasspath("target/classes");
compiler.setSourcepath("src/test/java");
compiler.setDestinationpath("target/hotswap");

// Create a ProxyClass.  A monitor is setup that watches for
// source files changes in the file.
ProxyClass cls = compiler.load("org.example.MatrixTransformer");

// Create a Proxy object that implements Transformer
Transformer t = (Transformer)cls.newInstance();

// Before the transform method is actually invoked, a check is performed
// to see if the source file has changed.  If so, the class is
// recompiled and the object instance is swapped out.  The result
// object will have been generated by the updated code.  Cool!
Object input = ...
Object output = t.transform(input);