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ASM - How can I convert Java class name from Java bytecode name?

I'm using ASM (a bytecode modification library) and it provides access to type names in the bytecode naming format, for example a String field is reported to have the description: Ljava/lang/String

I need to invoke Class.forName for some classes, but I need the source code form of the type names for that, e.g. java.lang.String.

Is there a way of converting from internal name to Java source format?

Solution

  • I don't know any API method, but the conversion is quite simple. You cand find details in JVM spec here. Primitive types are represented by one character:

    B = byte
    C = char
    D = double
    F = float
    I = int
    J = long
    S = short
    Z = boolean

    Class and interface types are represented by the fully qualified name, with an 'L' prefix and a ';' suffix. The dots '.' in the fully qualified class name are replaced by '/' (for inner classes, the '.' separating the outer class name from the inner class name is replaced by a '$'). So the internal name of the String class would be "Ljava/lang/String;" and the internal name of the inner class "java.awt.geom.Arc2D.Float" would be "Ljava/awt/geom/Arc2D$Float;".

    Array names begin with an opening bracket '[' followed by the component type name (primitive or reference). An "int[]" thus becomes "[I" and a "javax.swing.JFrame[][]" becomes "[[Ljavax.swing.JFrame;".