This is a basic class file reader which supports reading class files with major version 61 and below. Currently, we only read required information from the class file (up to the super_class entry).

Usage

Create a ClassFileReader instance and call the read() method to start reading the class file.

// Kotlin
val reader = ClassFileReader(FileInputStream(File("/path/to/MyClass.class"))) 
val classFile = reader.read()

Constant pool

The IClassFile provides access to the constant pool that is read from the class file.

The entries in the constant pool from class file is represented by the IConstant implementations. Each implementation has a type property which represents the type of the constant. It also contains the tag value of the constant type. The following table shows the constant type and its implementation in this class file reader.

Constant type	Implementation
CONSTANT_Class	`ClassConstant`
CONSTANT_Fieldref	`ReferenceConstant`
CONSTANT_Methodref	`ReferenceConstant`
CONSTANT_InterfaceMethodref	`ReferenceConstant`
CONSTANT_String	`StringConstant`
CONSTANT_Integer	`IntegerConstant`
CONSTANT_Float	`FloatConstant`
CONSTANT_Double	`DoubleConstant`
CONSTANT_NameAndType	`NameAndTypeConstant`
CONSTANT_Utf8	`Utf8Constant`
CONSTANT_MethodHandle	`MethodHandleConstant`
CONSTANT_MethodType	`MethodTypeConstant`
CONSTANT_Dynamic	`DynamicConstant`
CONSTANT_InvokeDynamic	`DynamicConstant`
CONSTANT_Module	`ModuleConstant`
CONSTANT_Package	`PackageConstant`

References

The following sections were referred from the JDK 17 JVM specifications :