Java Class Viewer

The Best Class File Visual Inspector

Java Class Viewer

The Java Class Viewer (jCV) is a visual class file inspector. It can open .class, .jar, files, etc.

By using jCV, you can see the meaning of each byte in the class file.

jCV Main Window

A class file is a stream of 8-bit bytes; it has the following structure, as described in JVM Spec:

    ClassFile {
        u4 magic;
        u2 minor_version;
        u2 major_version;
        u2 constant_pool_count;
        cp_info constant_pool[constant_pool_count-1];
        u2 access_flags;
        u2 this_class;
        u2 super_class;
        u2 interfaces_count;
        u2 interfaces[interfaces_count];
        u2 fields_count;
        field_info fields[fields_count];
        u2 methods_count;
        method_info methods[methods_count];
        u2 attributes_count;
        attribute_info attributes[attributes_count];
    }
    

The Java Class Viewer is displaying the class file in two panels. The left panel is a tree just exactly as the ClassFile structure; the right panel includes a binary viewer. When you select a component in the tree node, the corresponding bytes for the component will be selected automatically.