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The extends CONSTANT_CELL(class) clause places the "super" element of the class file. The implements INTERFACES clause places the table of interfaces. Since the assembler does not distinguish interfaces and ordinary classes (the only difference is one access bit), the table of interfaces of an interface class must be declared with implements keyword, and not extends, as in Java language.

Note:The last two rules allow TOP_LEVEL_COMPONENT to appear in any order and number. For example, you can split constant pool table into several parts, mixing constants and method declarations.

General Source File Structure

Package declaration can appear only once in source file.


The Constant Pool and Constant Elements

A CONSTANT_CELL refers to an element in the constant pool. It may refer to the element either by its index or its value:

Generic rule for TAGGED_CONSTANT_VALUE is:

A TAG may be omitted when the context only allows one kind of a tag. For example, the argument of an anewarray instruction should be a CONSTANT_CELL which represents a class, so instead of

    anewarray class java/lang/Object

one may write:

    anewarray java/lang/Object

It is possible to write another tag, e.g.:

    anewarray String java/lang/Object

However, the resulting program will be incorrect.

Another example of an implicit tag (eg. a context which implies tag) is the header of a class declaration. You may write:

    aClass {
    }

which is equivalent to:

    class aClass {
    }

Below, the tag implied by context will be included in the rules, e.g.:

    CONSTANT_VALUE(int).

The exact notation of CONSTANT_VALUE depends on the (explicit or implicit) TAG.

int INTEGER  
long [INTEGER|LONG]  
float [FLOAT|INTEGER]  
float bits INTEGER  
double [FLOAT|DOUBLE|INTEGER|LONG]  
double [bits INTEGER | bits LONG]  
Asciz EXTERNAL_NAME  
class CONSTANT_NAME  
String CONSTANT_NAME  
NameAndType NAME_AND_TYPE  
Field CONSTANT_FIELD  
Method CONSTANT_FIELD  
MethodHandle INVOKESUBTAG : CONSTANT_FIELD
[FIELDREF|METHODREF|INTERFACEMETHODREF]
MethodType CONSTANT_NAME
InvokeDynamic INVOKESUBTAG : CONSTANT_FIELD

Note

When the JASM parser encounters an InvokeDynamic constant, it creates an entry in the BootstrapMethods attribute (the BootstrapMethods attribute is produced if it has not already been created). The entry contains a reference to the MethodHandle item in the constant pool, and, optionally, a sequence of references to additional static arguments (ldc-type constants) to the bootstrap method.

INVOKESUBTAGs for MethodHandle and (const) InvokeDynamic are defined as follows:

REF_GETFIELD [1]
REF_GETSTATIC [2]
REF_PUTFIELD [3]
REF_PUTSTATIC [4]
REF_INVOKEVIRTUAL [5]
REF_INVOKESTATIC [6]
REF_INVOKESPECIAL [7]
REF_NEWINVOKESPECIAL [8]
REF_INVOKEINTERFACE [9]

Static arguments for an InvokeDynamic constant are defined as follows:

int INTEGER
long [INTEGER|LONG]
float [FLOAT|INTEGER]
double [FLOAT|DOUBLE|INTEGER|LONG]
class CONSTANT_NAME
String CONSTANT_NAME
MethodHandle INVOKESUBTAG:CONSTANT_FIELD
MethodType CONSTANT_NAME

 

INTEGER, LONG, FLOAT, and DOUBLE correspond to IntegerLiteral and FloatingPointLiteral as described in The Java Language Specification. If a double-word constant (LONG or DOUBLE) is represented with a single-word value (INTEGER or FLOAT, respectively), single-word value is simply promoted to double-word, as described in The Java Language Specification. If floating-point constant (FLOAT or DOUBLE) is represented with an integral value (INTEGER or LONG, respectively), the result depends on whether the integral number is preceded with the keyword "bits". If "bits" is not used, the result is a floating-point number closest in value to the decimal number. If the keyword "bits" is used, the floating-point constant takes bits of the integral value without conversion.

Thus,

   float 2;

means the same as

   float 2.0f;

and the same as

   float bits 0x40000000;

while

   float bits 2;

actually means the same as

   float bits 0x00000002;

and the same as

   float 2.8026e-45f

 

External names are names of class, method, field, or type, which stay in resulting .class file, and may be represented both by IDENT or by STRING (which is useful when name contains non-letter characters).

In this second example, the first CONSTANT_NAME denotes the name of a field and second denotes its type.

In this third example, CONSTANT_NAME denotes to the class of a field. If CONSTANT_NAME is omitted, the current class is assumed.

Constant Declarations

Constant declarations are demonstrated in the examples below:

Info
iconfalse
	const #1=int 1234
	    , #2=String "a string"
	    , #3=Method get:I
	;

Field Variables

Example:

Info
iconfalse
	public static Field 
	    field1:I = int 1234,
	    field2:S 
	;

Access bits (public and static) are applied both to field1 and field2. The EXTERNAL_NAME denotes the name of the field, CONSTANT_NAME denotes its type, TAGGED_CONSTANT_VALUEdenotes initial value.

 

Method Declarations

The EXTERNAL_NAME denotes the name of the method, CONSTANT_NAME denotes its type.

The meaning of the THROWS clause is the same as in Java Language Specification - it forms Exceptions attribute of a method. Jasm itself does not use this attribute in any way.

The NUMBER denotes maximum operand stack size of the method.

The NUMBERdenotes number of local variables of the method. If omitted, it is calculated by assembler according to the signature of the method and local variable declarations.

 

Instructions

 

VM Instructions

Jasm allows for a NUMBER (which is ignored) at the beginning of each line. This is allowed in order to remain consistent with the jdis disassembler. Jdis puts line numbers in disassembled code that may be reassembled using Jasm without any additional modifications.

SWITCHTABLE example: Java_text

Note
iconfalse
     switch (x) {
     	case 11:
	 		x=1;
	 		break;
     	case 12:
	 		x=2;
	 		break;
     	default:
	 		x=3;
     }

will be coded in assembler as follows:

Info
iconfalse
tableswitch  {
	 11: L24;
	 12: L29;
	 default: L34
     }
L24: iconst_1; 
     istore_1;
     goto  L36;
L29: iconst_2 ;
     istore_1;
     goto  L36;
L34: iconst_3; 
     istore_1;
L36:    ....

OPCODE is any mnemocode from the instruction set. If mnemocode needs an ARGUMENT, it cannot be omitted. Moreover, the kind (and number) of the argument(s) must match the kind (and number) required by the mnemocode:

 

aload, astore, fload, fstore, iload, istore, lload, lstore, dload, dstore, ver, endvar:LOCAL_VARIABLE
iinc:LOCAL_VARIABLE, NUMBER
sipush, bipush, bytecode:NUMBER
tableswitch, lookupswitch:SWITCHTABLE
newarray:TYPE
jsr, goto, ifeq, ifge, ifgt, ifle, iflt, ifne, if_icmpeq, if_icmpne, if_icmpge, if_icmpgt, if_icmple, if_icmplt, if_acmpeq, if_acmpne, ifnull, ifnonnull, try, endtry:LABEL
jsr_w, goto_w:LABEL
ldc_w, ldc2_w, ldc:CONSTANT_CELL
new, anewarray, instanceof, checkcast,CONSTANT_CELL(class)
multianewarrayNUMBER, CONSTANT_CELL(class)
putstatic, getstatic, putfield, getfield:CONSTANT_CELL(Field)
invokevirtual, invokenonvirtual, invokestatic:CONSTANT_CELL(Method)
invokeinterface:NUMBER, CONSTANT_CELL(Method)
invokedynamic:CONSTANT_CELL(InvokeDynamic)
 aaload,  aastore,  aconst_null,  aload_0,  aload_1,  aload_2,  aload_3,  aload_w ,  areturn,  arraylength,  astore_0,  astore_1,  astore_2,  astore_3,  astore_w,  athrow,  baload,  bastore,  caload,  castore,  d2f,  d2i,  d2l,  dadd,  daload,  dastore,  dcmpg,  dcmpl,  dconst_0,  dconst_1,  ddiv,  dead,  dload_0,  dload_1,  dload_2,  dload_3,  dload_w ,  dmul,  dneg,  drem,  dreturn,  dstore_0,  dstore_1,  dstore_2,  dstore_3,  dstore_w,  dsub,  dup,  dup2,  dup2_x1,  dup2_x2,  dup_x1,  dup_x2,  f2d,  f2i,  f2l,  fadd,  faload,  fastore,  fcmpg,  fcmpl,  fconst_0,  fconst_1,  fconst_2,  fdiv,  fload_0,  fload_1,  fload_2,  fload_3,  fload_w,  fmul,  fneg,  frem,  freturn ,  fstore_0,  fstore_1,  fstore_2,  fstore_3,  fstore_w,  fsub ,  i2b,  i2c,  i2d,  i2f,  i2l,  i2s,  iadd,  iaload,  iand,  iastore,  iconst_0,  iconst_1,  iconst_2,  iconst_3,  iconst_4,  iconst_5,  iconst_m1,  idiv,  iinc_w,  iload_0,  iload_1,  iload_2,  iload_3,  iload_w,  imul,  ineg,  int2byte,  int2char,  int2short,  ior,  irem,  ireturn,  ishl,  ishr,  istore_0,  istore_1,  istore_2,  istore_3,  istore_w,  isub,  iushr,  ixor,  l2d,  l2f,  l2i,  label,  ladd,  laload,  land,  lastore,  lcmp,  lconst_0,  lconst_1,  ldiv,  lload_0,  lload_1,  lload_2,  lload_3,  lload_w,  lmul,  lneg,  lor,  lrem,  lreturn,  lshl,  lshr,  lstore_0,  lstore_1,  lstore_2,  lstore_3,  lstore_w,  lsub,  lushr,  lxor,  monitorenter,  monitorexit,  nonpriv,  nop,  pop,  pop2,  priv,  ret,  return,  ret_w,  saload,  sastore,  swap,   wide<No Arguments>

InvokeDynamic Instructions

InvokeDynamic instructions are instructions that allow dynamic binding of methods to a call site. These instructions in JASM form are rather complex, and the JASM assembler does some of the necessary work to create a BootstrapMethods attribute for entries of binding methods.

Info
iconfalse
class Test
        version 51:0
{


   Method m:"()V"
     stack 0 locals 1
   {
       invokedynamic REF_invokeSpecial:bsmName:"()V"  // information about bootstrap method
                                      :methName:"(I)I" // dynamic call-site name ("methName") plus the argument and return types of the call ("(I)I")
                                      int 1, long 2l;  // optional sequence of additional static arguments to the bootstrap method (ldc-type constants)
   }

} // end Class Test

 

his JASM code has an invokedynamic instruction of the form: invokedynamic (CONSTANT_CELL(INVOKEDYNAMIC)) where the INVOKEDYNAMIC constant is represented as specified

(i.e. invokedynamic INVOKESUBTAG : CONSTANT_FIELD (bootstrapmethod signature) : NAME_AND_TYPE (CallSite) [Arguments (Optional)]).

The JASM assembler creates the appropriate constant entries and entries into the BootstrapMethods attribute in a resulting class file.

You can also create InvokeDynamic constants and BootstrapMethods explicitly:

Info
iconfalse
	#22; //class Test3
	version 51:0
{

const #1 = InvokeDynamic	0:#11;	//  REF_invokeSpecial:Test3.bsmName:"()V":name:"(I)I" int 1, long 2l
const #2 = Asciz	"Test3";
const #3 = long	2l;
const #5 = class	#6;	//  java/lang/Object
const #6 = Asciz	"java/lang/Object";
const #7 = Asciz	"name";
const #8 = int	1;
const #9 = Asciz	"SourceFile";
const #10 = Asciz	"Test3.jasm";
const #11 = NameAndType	#7:#21;	//  name:"(I)I"
const #12 = Asciz	"()V";
const #13 = Method	#22.#17;	//  Test3.bsmName:"()V"
const #14 = Asciz	"Code";
const #15 = Asciz	"m";
const #16 = Asciz	"BootstrapMethods";
const #17 = NameAndType	#20:#12;	//  bsmName:"()V"
const #18 = Asciz	"LineNumberTable";
const #19 = MethodHandle	7:#13;	//  REF_invokeSpecial:Test3.bsmName:"()V"
const #20 = Asciz	"bsmName";
const #21 = Asciz	"(I)I";
const #22 = class	#2;	//  Test3
const #23 = class	#6;	//  java/lang/Object



Method #15:#12
	stack 0 locals 1
{
	0:	invokedynamic	#1; //	InvokeDynamic REF_invokeSpecial:Test3.bsmName:"()V":name:"(I)I" int 1, long 2l;
}

BootstrapMethod #19 #8 #3;

} // end Class Test3

 

In this example, const #1 = InvokeDynamic 0:#11; is the InvokeDynamic constant that refers to BootstrapMethod at index '0' in the BootstrapMethods Attribute (BootstrapMethod #19 #8 #3; which refers to the MethodHandle at const #19, plus 2 other static args (at const #8 and const #3).

 

Pseudo Instructions

Pseudo instructions are 'assembler directives', and not really instructions (in the VM sense) They typically come in two forms: Code-generating Pseudo-Instructions, and Attribute-Generating Pseudo-Instructions.

Code-Generating Pseudo-Instructions

The bytecode directive instructs the assembler to put a collection of raw bytes into the code attribute of a methodK

Attribute-Generating Pseudo-Instructions

The rest of pseudo_instructions do not produce any bytecodes, and are used to form tables: local variable table, exception table,
Stack Maps, and Stack Map Frames. Line Number Tables can not be specified, but they are constructed by the assembler itself.

 

Local Variable Table Attribute Generation

Example:

Note
iconfalse
static void main (String[] args) {
	Tester inst = new Tester();
    inst.callSub();
}

 

will be coded in assembler as follows:

Info
iconfalse
static Method #8:#9	 // main:"([Ljava/lang/String;)V"
	stack 2 locals 2
{
4 var 0; // args:"[Ljava/lang/String;"
	0:	new	#1; //	class Tester;
	3:	dup;
	4:	invokespecial	#2; //	Method "<init>":"()V";
	7:	astore_1;
6 var 1; // inst:"LTester;"
	8:	aload_1;
	9:	invokevirtual	#3; //	Method callSub:"()V";
7	12:	return;
 endvar 0, 1;
	
}

 

 

Exception Table Attribute Generation

To generate exception table, three pseudo-instructions are used.

TRAP_IDENT represents the name or number of an exception table entry. CONSTANT_CELL in "catch" pseudo_instruction means catch type. Each exception table entry contains 4 values:start-pc, end-pc, catch-pc, catch-type. In jasm, each entry is denoted with some (local) identifier, as an example: TRAP_IDENT.

To set start-pc, place "try TRAP_IDENT" before the instruction with the desirable program counter. Similarly, use "endtry TRAP_IDENT" for end-pc and "catch TRAP_IDENT, catch-type" for catch-pc and catch-type (which is usually a constant pool reference). Try, endtry, and catch pseudoinstructions may be placed in any order. The order of entries in exception table is significant (see JVM specification). However, the only way to control this order is to place catch-clauses in appropriate textual order: assembler adds an entry in the exception table each time it encounters a catch-clause.

Example:

Note
iconfalse
    try {
	     try {
		 	throw new Exception("EXC");
	     } catch (NullPointerException e){
		 	throw e;
	     } catch (Exception e){
		 	throw e;
	     }
	 } catch (Throwable e){
		 throw e;
	 }

 

will be coded in assembler as follows:

Code Blockinfo
iconfalse
themeEmacs
languagecpp
titleExceptionTableAttribute
try R1, R2; // single "try" or "endtry" can start several regions
		new	class java/lang/Exception;
		dup;
		ldc	String "EXC";
		invokespecial java/lang/Exception.<init>:"(Ljava/lang/String;)V";
		athrow;
 endtry R1;
 catch R1 java/lang/NullPointerException; // only one "catch" per entry allowed
		astore_1;
		aload_1;
		athrow;
 catch R1 java/lang/Exception; // same region (R1) can appear in different catches
		astore_1;
		aload_1;
		athrow;
 endtry R2;
 catch R2 java/lang/Throwable;
		astore_1;
		aload_1;
		athrow;

 

StackMap Table Attribute Generation

Stack Maps are denoted by the pseudo-op opcode stack_map, and they can be identified by three basic items:

stackMap_Item_MapType = (bogus | int | float | double | long | null | this | CP)

stackMap_Item_Object = CONSTANT_CELL_CLASS
stackMap_Item_NewObject = at LABEL

All stack_map directives are collected by the assembler, and are used to create a StackMap Table attribute.

Example 1 (MapType):

Info
iconfalse
public Method "<init>":"()V"
    stack 1 locals 1
{
        aload_0;
        invokespecial    Method java/lang/Object."<init>":"()V";
        return;
        stack_frame_type full;
        stack_map bogus;
        ...
}


Example 2 (Object):

Info
iconfalse

public Method "<init>":"()V"
    stack 2 locals 1
{
        ...
        stack_map class java/lang/Object;
        nop;
        return;
}



Example 3 (NewObject):

Info
iconfalse

public Method "<init>":"()V"
    stack 2 locals 1
{
        ...
        stack_map at L5;
        nop;
        return;
}




StackFrameType Table Attribute Generation

StackFrameTypes are similar assembler directives as StackMap. These directives can appear anywhere in the code, and the assembler will collect them to produce a StackFrameType attribute.

frame_type = ( same | stack1 | stack1_ex | chop1 | chop2 | chop3 | same_ex | append | full )

Example 1 (full stack frame type):

 

Info
iconfalse
public Method "<init>":"()V"
    stack 1 locals 1
{
        aload_0;
        invokespecial    Method java/lang/Object."<init>":"()V";
        return;
        stack_frame_type full;
        stack_map bogus;
        ...
}

 

Example 2 (append, chop2, and same stack frame types):

 

Info
iconfalse
public Method foo:"(Z)V"
	stack 2 locals 5
{
        ...
		iload_2;
		iconst_2;
		if_icmpge	L30;
 L27: stack_frame_type append;
		locals_map int, int;
		iconst_2;
		istore	4;
 L30: stack_frame_type chop2;
		goto	L9;
 L33: stack_frame_type same;
		getstatic	Field java/lang/System.out:"Ljava/io/PrintStream;";
		ldc	String "Chop2 attribute test";
		invokevirtual	Method java/io/PrintStream.println:"(Ljava/lang/String;)V";
		return;
        ...
}

 

 
LocalsMap Table

Locals Maps are typically associated with a stack_frame_type, and are accumulated per stack frame. They typically follow a stack_frame_type directive.

locals_type = stackMap_Item_MapType | CONSTANT_CELL_CLASS

Example (a locals map specifying 2 ints):

 

Info
iconfalse
public Method foo:"(Z)V"
	stack 2 locals 5
{
        ...
		iload_2;
		iconst_2;
		if_icmpge	L30;
	L27:	stack_frame_type append;
 locals_map int, int;
		iconst_2;
		istore	4;
	L30:	stack_frame_type chop2;
		goto	L9;
	L33:	stack_frame_type same;
		getstatic	Field java/lang/System.out:"Ljava/io/PrintStream;";
		ldc	String "Chop2 attribute test";
		invokevirtual	Method java/io/PrintStream.println:"(Ljava/lang/String;)V";
		return;
        ...
}

Inner-Class Declarations

Example:

Info
iconfalse
    InnerClass InCl=class test$InCl of class test;

Annotation Declarations

Member Annotations

Member annotations are a subset of the basic annotations support provided in JDK 5.0 (1.5). These are annotations that ornament Packages, Classes, and Members either visibly (accessible at runtime) or invisibly (not accessible at runtime). In JASM, visible annotations are denoted by the token @, while invisible annotations are denoted by the token @-.

Synopsis

The '@+' token identifies a Runtime Visible Annotation, where the '@-' token identifies a Runtime Invisible Annotation.

Note
    Types (Boolean, Byte, Char, and Short) are normalized into Integer's within the constant pool.
    Annotation values with these types may be identified with a keyword in front of an integer value.

     eg.       boolean true (or: boolean 1)
                 byte 20
                 char 97
                 short 2130

    Other primitive types are parsed according to normal prefix and suffix conventions
    (eg. Double = xxx.xd, Float = xxx.xf, Long = xxxL). 
    Strings are identified and delimited by '"' (quotation marks).

   Keywords 'class' and 'enum' identify those annotation types explicitly. Values within classes and enums may
   either be identifiers (strings) or Constant Pool IDs.

   Annotations specified as the value of an Annotation field are identified by the JASM annotation keywords '@+' and '@-'.

   Arrays are delimited by '{' and '}' marks, with individual elements delimited by ',' (comma).

Examples

Example 1 (Class Annotation, Visible)

 

Info
iconfalse
@+ClassPreamble { 
     author = "John Doe", 
     date = "3/17/2002", 
     currentRevision = 6, 
     lastModified = "4/12/2004", 
     lastModifiedBy = "Jane Doe", 
     reviewers = {
        "Alice",
        "Bob",
        "Cindy"}
}
super public class MyClass
	version 50:0
{
 ...

 

Example 2 (Field Annotation, Invisible)
Info
iconfalse
@-FieldPreamble {
     author = "Mustafa", 
     date = "3/17/2009", 
     currentRevision = 4
}
Field foo:I;

...





Example 3 (Field Annotation, All subtypes)
Info
iconfalse
@+FieldPreamble { 
	boolAnnot      = boolean 1, 					// Boolean
	charBear       = char 97, 					// Char
	sharkByte      = byte 17, 					// Byte
	shortCircuit   = short 4386,					// Short 
	integerHead    = 42,						// Int 
	longJohnSilver = 55l,						// Long 
	floatBoat      = 1.0f,						// Float 
	doubleDip      = 10.0d,						// Double 
	stringBeans    = "foo",						// String 
	severity       = enum FieldPreamble$Severity IMPORTANT,   	// Enum
	classAnnot     = class FieldPreamble$FooBall,			// Class
	tm = @+Trademark { description = "embedded", owner = "ktl"}	// Annotation
}
Field foo:I;

...


 

Note:
 JASM does not enforce the annotation value declarations like a compiler would.  It only checks to see that an annotation structure is well-formed.

Type Annotations

Member annotations are a subset of the basic annotations support provided in JDK 7.0 (1.7). These are annotations that ornament Packages, Classes, and Members either visibly (accessible at runtime) or invisibly (not accessible at runtime). In JASM, visible annotations are denoted by the token @T+, while invisible annotations are denoted by the token @T-.

Synopsis

TYPE_ANNOTATION_DECLARATION:@T+|@T- ANNOTATION_NAME [TYPE_ANNOTATION_VALUE_DECLARATIONS]

TYPE_ANNOTATION_VALUE_DECLARATIONS: list of (comma separated)
TYPE_ANNOTATION_VALUE_DECLARATION

TYPE_ANNOTATION_VALUE_DECLARATION:{ { ANNOTATION_VALUE_DECLARATION+ } TARGET PATH }

TARGET:{ TARGET_TYPE TARGET_INFO }


TARGET_TYPE:
         

TARGET_TYPE:TARGET_INFO_TYPE:
CLASS_TYPE_PARAMETER TYPEPARAM
METHOD_TYPE_PARAMETER  TYPEPARAM
CLASS_EXTENDS SUPERTYPE
CLASS_TYPE_PARAMETER_BOUND TYPEPARAM_BOUND
METHOD_TYPE_PARAMETER_BOUNDTYPEPARAM_BOUND
FIELD EMPTY
METHOD_RETURN EMPTY|
METHOD_RECEIVEREMPTY
METHOD_FORMAL_PARAMETERMETHODPARAM
THROWSEXCEPTION
LOCAL_VARIABLELOCALVAR
RESOURCE_VARIABLELOCALVAR
EXCEPTION_PARAMCATCH
INSTANCEOFOFFSET
NEWOFFSET
CONSTRUCTOR_REFERE CE_RECEIVEROFFSET
METHOD_REFERENCE_RECEIVEROFFSET 
CASTTYPEARG
CONSTRUCTOR_INVOCATION_TYPE_ARGUMENTTYPEARG
METHOD_INVOCATION_TYPE_ARGUMENTTYPEARG
CONSTRUCTOR_REFERENCE_TYPE_ARGUMENTTYPEARG
METHOD_REFERENCE_TYPE_ARGUMENTTYPEARG

 

TARGET_INFO_TYPE: TYPEPARAM | SUPERTYPE | TYPEPARAM_BOUND | EMPTY | METHODPARAM | EXCEPTION | LOCALVAR | CATCH | OFFSET |  TYPEARG
TYPEPARAM:
paramIndex(INTEGER)


SUPERTYPE:
typeIndex(INTEGER)typeIndex(INTEGER)

TYPEPARAM_BOUND:
paramIndex(INTEGER) boundIndex(INTEGER)


EMPTY: 


METHODPARAM:
index(paramIndex(INTEGER)
EXCEPTION:
typeIndex(INTEGER) 


LOCALVAR:
{ LVENTRY }+numEntries

LVENTRY:
startpc(INTEGER) length(INTEGER) index(INTEGER) 
offset(INTEGER)
TYPEARG:
offset(INTEGER) typeIndex(INTEGER)


 PATH: list of (space separated)
{ PATH_ENTRY+ }
 { PATH_KIND PATH_INDEX }

 


PATH_KIND: ARRAY | INNER_TYPE | WILDCARD | TYPE_ARGUMENT

PATH_INDEX:
INTEGER





Parameter Names and Parameter Annotations

Parameter annotations are another subset of the basic annotations support provided in JDK 5.0 (1.5). These are annotations that ornament Parameters to methods either visibly (accessible at runtime) or invisibly (not accessible at runtime). In JASM, visible parameter annotations are denoted by the token @+, while invisible parameter annotations are denoted by the token @-.

Parameter names come from an attribute introduced in JDK 8.0 (1.8).  These are fixed parameter names that are used to ornament parameters on methods.  In Jasm, parameter names are identified by the token # followed by { } braclets

Synopsis

Examples

Example 1 (Parameter Annotation)
Java Code

 

Note
iconfalse
public class MyClass2 {
	
 ...

    public int doSomething(
	@VisParamPreamble ( author = "gummy" )  @InVisParamPreamble ( author = "bears" )  int barber,
	boolean of, 
        @VisParamPreamble ( author = "sour" )  @InVisParamPreamble ( author = "worms" )    int seville,
        @InVisParamPreamble1 ( reviewers = {"Dilbert", "Garfield"} ) boolean pastrami) { 
         ...
    }
 ...
}

 

JASM Code

Note:  The first two parameters are named ('P0'- 'P3').  Since this is a compiler controlled option, there is no way to specify parameter naming in Java source.

 

Info
iconfalse
super public class MyClass2
	version 50:0
{
 ...

  public Method doSomething:"(IZIZ)I"
	stack 2 locals 5

	0: #{P0 mandated} @+VisParamPreamble { author = "gummy" } @-InVisParamPreamble { author = "bears" } 
	1: #{P1 final synthetic mandated}
        2: #{P2 mandated} @+VisParamPreamble { author = "sour" } @-InVisParamPreamble { author = "worms" } 
	3: #{P3 mandated} @-InVisParamPreamble1 { reviewers = {  "Dilbert",  "Garfield"} } 
   {
	...
   }

} // end Class MyClass2

 

Default Annotations

  Default annotations are another subset of the basic annotations support provided in JDK 5.0 (1.5). These are annotations that ornament Annotations either visibly (accessible at runtime) or invisibly (not accessible at runtime). Default annotations specify a default value for a given annotation field.

Synopsis

Examples

Example 1 (Default Annotation)
Java Code

 

Note
iconfalse
import java.lang.annotation.*; 

@Retention(RetentionPolicy.RUNTIME)
@interface Meth2Preamble {
   String author() default "John Steinbeck";
}


JASM Code

 

Info
iconfalse
interface  Meth2Preamble
    implements java/lang/annotation/Annotation
    version 50:0
{
   public abstract Method author:"()Ljava/lang/String;" default { "John Steinbeck" } ;
} // end Class Meth2Preamble

 

PicoJava Instructions

These instructions takes 2 bytes: prefix (254 for non-privileged variant and 255 for privileged) and the opcode itself. These instructions can be coded in assembler in 2 ways: as single mnemocode identical to the description or using "priv" and "nonpriv" instructions followed with an integer representing the opcode.

 



CATCH:

catch(INTEGER)


OFFSET:


PATH_ENTRY:

 

Appendix B

 

 

 

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