Java位元組碼指令

Java 位元組碼指令及javap 使用說明

### java位元組碼指令列表

JVM指令助記符

變數到運算元棧：iload,iload_,lload,lload_,fload,fload_,dload,dload_,aload,aload_
運算元棧到變數：istore,istore_,lstore,lstore_,fstore,fstore_,dstore,dstor_,astore,astore_
常數到運算元棧：bipush,sipush,ldc,ldc_w,ldc2_w,aconst_null,iconst_ml,iconst_,lconst_,fconst_,dconst_
加：iadd,ladd,fadd,dadd
減：is ,ls ,fs ,ds
乘：imul,lmul,fmul,dmul
除：idiv,ldiv,fdiv,ddiv
餘數：irem,lrem,frem,drem
取負：ineg,lneg,fneg,dneg
移位：ishl,lshr,iushr,lshl,lshr,lushr
按位或：ior,lor
按位與：iand,land
按位異或：ixor,lxor
型別轉換：i2l,i2f,i2d,l2f,l2d,f2d(放寬數值轉換)
i2b,i2c,i2s,l2i,f2i,f2l,d2i,d2l,d2f(縮窄數值轉換)

建立類實便：new
建立新陣列：newarray,anewarray,multianwarray
訪問類的域和類例項域：getfield,putfield,getstatic,putstatic
把資料裝載到運算元棧：baload,caload,saload,iaload,laload,faload,daload,aaload
從運算元棧存儲存到陣列：bastore,castore,sastore,iastore,lastore,fastore,dastore,aastore
獲取陣列長度：arraylength
檢相類例項或陣列屬性：instanceof,checkcast
運算元棧管理：pop,pop2,dup,dup2,dup_xl,dup2_xl,dup_x2,dup2_x2,swap
有條件轉移：ifeq,iflt,ifle,ifne,ifgt,ifge,ifnull,ifnonnull,if_icmpeq,if_icmpene,
if_icmplt,if_icmpgt,if_icmple,if_icmpge,if_acmpeq,if_acmpne,lcmp,fcmpl
fcmpg,dcmpl,dcmpg
複合條件轉移：tableswitch,lookupswitch
無條件轉移：goto,goto_w,jsr,jsr_w,ret
排程物件的實便方法：invokevirt l
呼叫由介面實現的方法：invokeinterface
呼叫需要特殊處理的例項方法：invokespecial
呼叫命名類中的靜態方法：invokestatic
方法返回：ireturn,lreturn,freturn,dreturn,areturn,return
異常：athrow
finally關鍵字的實現使用：jsr,jsr_w,ret

javap

-help
Prints out help message for javap.
-l
Prints out line and local variable tables.
-b
Ensures backward compatibility with javap in JDK 1.1.
-p lic
Shows only p lic classes and members.
-protected
Shows only protected and p lic classes and members.
-package
Shows only package, protected, and p lic classes and members. This is the default.
-private
Shows all classes and members.
-Jflag
Pass flag directly to the runtime system. Some examples:

javap -J-version
javap -J-Djava.security.manager -J-Djava.security.policy=MyPolicy MyClassName

-s
Prints internal type signatures.
-c
Prints out disassembled code, i.e., the instr tions that comprise the Java bytecodes, for each of the methods in the class. These are documented in the Java Virt l Machine Specification.
-verbose
Prints stack size, number of locals and args for methods.
-classpath path
Specifies the path javap uses to look up classes. Overrides the default or the CLASSPATH environment variable if it is set. Directories are separated by semi-colons. Thus the general format for path is:
.;
For example:
.;C:\usrs\dac\classes;C:\tools\java\classes
-bootclasspath path
Specifies path from which to load bootstrap classes. By default, the bootstrap classes are the classes implementing the core Java platform located in jre\lib\rt.jar and several other jar files.
-extdirs dirs