Examples of overriding groovy instance and static methods

Test.groovy

class Test {
    void method1() {
        println 'In method1'
    }

    void method1(String foo) {
        println "In method1 with String param of $foo"
    }

    static method2(String foo) {
        println "In static method2 with String param of $foo"
    }

    public static void main(String[] args) {

        def test = new Test()

        test.method1()
        test.method1("asdf")
        Test.method2("asdf")

        MetaMethod method1NoParamMethod = test.metaClass.pickMethod("method1", null as Class[])
        test.metaClass.method1 = { 
            println "augmenting no param method1"
            method1NoParamMethod.invoke(delegate)
        }

        MetaMethod method1StringParamMethod = test.metaClass.pickMethod("method1", String)
        test.metaClass.method1 = { String fooParam ->
            println "augmenting String param method1"
            method1StringParamMethod.invoke(delegate, fooParam)
        }

        MetaMethod method2Method = Test.metaClass.getStaticMetaMethod("method2", String)
        Test.metaClass.static.method2 = { String fooParam ->
            println "augmenting static method2"
            method2Method.invoke(delegate, fooParam)
        }

        test.method1()
        test.method1("asdf")
        Test.method2("asdf")

    }
}