public class MyExecution extends Execution {
	public MyExecution() {
		super(ExecutionCategory.CLEANING /* category */, "My execution" /* name */,
				"Executes something" /* description, can use html */);
	}
	/**
	* This method is invoked when the user clicks on the Run button
	* @return true if success, false if failure
	*/
	@Override
	public boolean execute(Map<String, Clazz> classes, boolean verbose) {
		classes.values().stream().map(c -> c.node).forEach(c -> {
			//transform the classes here using the tree-API of ASM
		});
		return false;
	}
}

public class MyExecution extends Execution implements IVMReferenceHandler {
	public MyExecution() {
		super(ExecutionCategory.GENERIC, "My execution", "Loads ClassNodes at runtime");
	}
	@Override
	public boolean execute(Map<String, Clazz> classes, boolean verbose) {
		classes.values().stream().map(c -> c.node).forEach(c -> {
			VM vm = VM.constructVM(this);
			//transform bytecode to java.lang.Class
			Class<?> loadedClass = vm.loadClass(c.name.replace('/', '.'), true);
			//do stuff with your class here
			loadedClass.getMethods()[0].invoke(...);
			return true;
		});
	}
	/**
	* Will get invoked by VM, when VM.loadClass is called
	*/
	@Override
	public ClassNode tryClassLoad(String name) {
		//try to find the class to be loaded in open jar archive
		return classes.containsKey(name) ? classes.get(name).node : null;
	}
}

public class MyExecution extends Execution implements IConstantReferenceHandler {
	public MyExecution() {
		super(ExecutionCategory.GENERIC, "My execution", "Performs stack analysis and replaces code.");
	}
	@Override
	public boolean execute(Map<String, Clazz> classes, boolean verbose) {
		classes.values().stream().map(c -> c.node).forEach(this::analyzeAndRewrite);
		return true;
	}
	public void analyzeAndRewrite(ClassNode cn) {
		cn.methods.forEach(m -> {
			// this analyzer keeps known stack values, e.g. can be useful for jump prediction
			Analyzer<ConstantValue> a = new Analyzer<ConstantValue>(new ConstantTracker(this, Access.isStatic(m.access), m.maxLocals, m.desc, new Object[0]));
			try {
				a.analyze(cn.name, m);
			} catch (AnalyzerException e) {
				logger.severe("Failed stack analysis in " + cn.name + "." + m.name + ":" + e.getMessage());
				return;
			}
			Frame<ConstantValue>[] frames = a.getFrames();
			InsnList rewrittenCode = new InsnList();
			Map<LabelNode, LabelNode> labels = Instructions.cloneLabels(m.instructions);

			// rewrite method instructions
			for (int i = 0; i < m.instructions.size(); i++) {
				AbstractInsnNode ain = m.instructions.get(i);
				Frame<ConstantValue> frame = frames[i];
				// replace / modify instructions, etc...
				if (frame.getStackSize() > 0) {
					ConstantValue top = frame.getStack(frame.getStackSize() - 1);
					if (top.isKnown() && top.isInteger()) {
						int knownTopStackValue = top.getInteger();
						// use the known stack to remove jumps, simplify code, etc...
						// if(...) { rewrittenCode.add(...); }
						continue;
					}
				}
				rewrittenCode.add(ain.clone(labels));
			}
			// update instructions and fix try catch blocks, local variables, etc...
			Instructions.updateInstructions(m, labels, rewrittenCode);
		});
	}
	/**
	 * Use this method to predict stack values if fields are loaded
	 */
	@Override
	public Object getFieldValueOrNull(BasicValue v, String owner, String name, String desc) {
		return null;
	}
	/**
	 * Use this method to predict stack values if methods are invoked on known objects
	 */
	@Override
	public Object getMethodReturnOrNull(BasicValue v, String owner, String name, String desc, List<? extends ConstantValue> values) {
		if (name.equals("toCharArray") && owner.equals("java/lang/String")) {
			if (!values.get(0).isKnown()) {
				// invocation target is not known, we can't compute the return
				return null;
			}
			return ((String) values.get(0).getValue()).toCharArray();
		}
		return null;
	}
}