List of Java bytecode instructions: Difference between revisions

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{{Short description|none}} <!-- This short description is INTENTIONALLY "none" - please see WP:SDNONE before you consider changing it! -->

{{Main|Java bytecode}}

This is a list of the instructions that make up the [[Java bytecode]], an abstract machine language that is ultimately executed by the [[Java virtual machine]].<ref>{{cite web|url=https://docs.oracle.com/javase/specs/jvms/se24/html/index.html |title=The Java® Virtual Machine Specification – Java SE 24 Edition |access-date=July 26, 2025}}</ref> The Java bytecode is generated from languages running on the [[Java Platform]], most notably the [[Java (programming language)|Java programming language]].

''Note that any referenced "value" refers to a 32-bit int as per the Java instruction set.''

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|-

! scope="col" | Mnemonic

! scope="col" | Opcode<br>''(in [[hexadecimal|hex]])''

!Opcode (in binary)

! scope="col" | Other bytes<br>[count]: [operand labels]

Line 942 ⟶ 943:

|1011 1010

|4: indexbyte1, indexbyte2, 0, 0

|[arg1, [arg2, ...]] → result

|invokes a dynamic method and puts the result on the stack (might be void); the method is identified by method reference ''index'' in constant pool ({{mono|indexbyte1 &lt;&lt; 8 {{pipe}} indexbyte2}})

|-

Line 1,064 ⟶ 1,065:

|int xor

|-

|jsr{{ref |Deprecated|†}}

|jsr

|data-sort-value=168|a8

|1010 1000

Line 1,071 ⟶ 1,072:

|jump to subroutine at ''branchoffset'' (signed short constructed from unsigned bytes {{mono|branchbyte1 &lt;&lt; 8 {{pipe}} branchbyte2}}) and place the return address on the stack

|-

|jsr_w{{ref |Deprecated|†}}

|data-sort-value=201|c9

|1100 1001

Line 1,393 ⟶ 1,394:

|set static field to ''value'' in a class, where the field is identified by a field reference ''index'' in constant pool ({{mono|indexbyte1 &lt;&lt; 8 {{pipe}} indexbyte2}})

|-

|ret{{ref |Deprecated|†}}

|ret

|data-sort-value=169|a9

|1010 1001

Line 1,457 ⟶ 1,458:

|-

|}

{{Refbegin}}

{{note label|Deprecated|†||Deprecated in Java 7 (major class version 51).<ref>{{cite web|url=https://docs.oracle.com/javase/specs/jvms/se24/html/jvms-4.html#jvms-4.9.1 |title=Chapter 4. The class File Format 4.9.1. Static Constraints |access-date=July 26, 2025}}</ref> They will not appear in class files generated from a compiler newer than that.}}

{{Refend}}

== See also ==

*[[Jazelle]] DBX (Direct Bytecode eXecution), a feature that executes some Java bytecodes in hardware, on some ARM9 CPUs

*[[Common Intermediate Language]] (CIL), a similar bytecode specification that runs on the CLR of the .NET Framework

*[[C to Java Virtual Machine compilers]]

== References ==

{{reflist}}

== External links ==

*[httphttps://docs.oracle.com/javase/specs/jvms/se12se24/html/indexjvms-6.html Oracle'sThe Java Virtual Machine Specification – Java SE 12Instruction EditionSet]

*[https://docs.oracle.com/javase/specs/jvms/se12/html/jvms-6.html The Java Virtual Machine Instruction Set]

{{Java (Sun)}}