Editing Name mangling (section)

====Creating unique names for inner and anonymous classes====
The scope of anonymous classes is confined to their parent class, so the compiler must produce a "qualified" public name for the [[inner class]], to avoid conflict where other classes with the same name (inner or not) exist in the same namespace. Similarly, anonymous classes must have "fake" public names generated for them (as the concept of anonymous classes only exists in the compiler, not the runtime). So, compiling the following Java program:

<syntaxhighlight lang="java">
public class foo {
    class bar {
        public int x;
    }

    public void zark () {
        Object f = new Object () {
            public String toString() {
                return "hello";
            }
        };
    }
}
</syntaxhighlight>

will produce three '''.class''' files:
* '''foo.class''', containing the main (outer) class ''foo''
* '''foo$bar.class''', containing the named inner class ''foo.bar''
* '''foo$1.class''', containing the anonymous inner class (local to method ''foo.zark'')

All of these class names are valid (as $ symbols are permitted in the JVM specification) and these names are "safe" for the compiler to generate, as the Java language definition advises not to use $ symbols in normal java class definitions.

Name resolution in Java is further complicated at runtime, as [[fully qualified name]]s for classes are unique only inside a specific [[classloader]] instance. Classloaders are ordered hierarchically and each Thread in the JVM has a so-called context class loader, so in cases where two different classloader instances contain classes with the same name, the system first tries to load the class using the root (or system) classloader and then goes down the hierarchy to the context class loader.