Truffle: Improved support for "probing" AST nodes: - Node.isSafelyReplacaeableBy(Node) checks in advance if Node.replace(Node) would be unsafe (crash the VM). - Hoist Probe() from language imlementations into Node; now completely language agnostic. - Language implementations support probing by implementing Node.isInstrumentable() and Node.createWrapperNode() - Node.Probe() throws ProbeException (without side effects) if the probe fails. -- ProbeException contains an instance of ProbeFailure that diagnoses the failure in detail - Additional measures to prevent instrumentation from being applied to internal InstrumentationNodes. - Promote ProbeListener to top level interface and add a default implementation

public class ClasspathDump {
    public static void main(String[] args) {
        System.out.print(System.getProperty("sun.boot.class.path"));
        System.out.print("|");
        System.out.print(System.getProperty("java.ext.dirs"));
        System.out.print("|");
        System.out.print(System.getProperty("java.endorsed.dirs"));
    }
}