file_formats_java_class provides the facilities for reading CLASS files defined in the Java Virtual Machine Specification, Java SE 7, CLASS major file version 51, chapter 4.

Supported Elements (Java SE 7)

• Class Access Flags (Table 4.1)
  • ACC_PUBLIC
  • ACC_FINAL
  • ACC_SUPER
  • ACC_INTERFACE
  • ACC_ABSTRACT
  • ACC_SYNTHETIC
  • ACC_ANNOTATION
  • ACC_ENUM
• Constant Pool (Table 4.3)
  • CONSTANT_Class_info
  • CONSTANT_Fieldref_info
  • CONSTANT_Methodref_info
  • CONSTANT_InterfaceMethodref_info
  • CONSTANT_String_info
  • CONSTANT_Integer_info
  • CONSTANT_Float_info
  • CONSTANT_Long_info
  • CONSTANT_Double_info
  • CONSTANT_NameAndType_info
  • CONSTANT_Utf8_info
  • CONSTANT_MethodHandle_info
  • CONSTANT_MethodType_info
  • CONSTANT_InvokeDynamic_info
• Field Access Flags (Table 4.4)
  • ACC_PUBLIC
  • ACC_PRIVATE
  • ACC_PROTECTED
  • ACC_STATIC
  • ACC_FINAL
  • ACC_VOLATILE
  • ACC_TRANSIENT
  • ACC_SYNTHETIC
  • ACC_ENUM
• Method Access Flags (Table 4.5)
  • ACC_PUBLIC
  • ACC_PRIVATE
  • ACC_PROTECTED
  • ACC_STATIC
  • ACC_FINAL
  • ACC_SYNCHRONIZED
  • ACC_BRIDGE
  • ACC_VARARGS
  • ACC_NATIVE
  • ACC_ABSTRACT
  • ACC_STRICT
  • ACC_SYNTHETIC
• Attributes (Table 4.6)
  • ConstantValue
  • Code
  • StackMapTable
  • Exceptions
  • InnerClasses
  • EnclosingMethod
  • Synthetic
  • Signature
  • SourceFile
  • SourceDebugExtension
  • LineNumberTable
  • LocalVariableTable
  • LocalVariableTypeTable
  • Deprecated
  • RuntimeVisibleAnnotations
  • RuntimeInvisibleAnnotations
  • RuntimeVisibleParameterAnnotations
  • RuntimeInvisibleParameterAnnotations
  • AnnotationDefault
  • BootstrapMethods
  • Other - Used for unrecognized/private attributes
  • NOTE: All restrictions put in place of each attribute for determining the validity of a CLASS file may not be fully implemented at the current time.

Example Use

All pertinent types and subprograms are available within the package File_Formats_Java_Class. Reading Class_File is done primarily through the Input aspect, as shown below.

with Ada.Text_IO;

with File_Formats_Java_Class;
use  File_Formats_Java_Class;

procedure Read_Class_File is
    F : File_Type;
    S : Stream_Access;
begin
    Open (F, In_File, "Example.class");
    S := Stream (F);
    Ada.Text_IO.Put_Line (Class_File'Input (S));
    Close (F);
end Read_Class_File;

Development Status

This crate does not yet define operations for writing to CLASS files, but this is a priority. After writing is complete, this crate will be updated to support CLASS files of Java SE 8+. You are free to report issues and contribute at the crate’s GitHub repository.