Java decompilation code analysis (1): java decompilation code analysis

Java decompilation code analysis (1): java decompilation code analysis

This article analyzes how to read such decompiled files.

Assignment

Node node;        Node node1 = _$3.getChildNodes().item(0);        node1;        node1;        JVM INSTR swap ;        node;        getChildNodes();        0;        item();        getChildNodes();        0;        item();        getNodeValue();        String s;        s;

Original statement:

Node node;Node node1 = currDocument.getChildNodes().item(0);node = node1;String s = node.getChildNodes().item(0).getChildNodes().item(0).getNodeValue();

// Value assignment statement // jvm instr swap;

Create an object without Parameters

JVM INSTR new #244 <Class CrossTable>;        JVM INSTR dup ;        JVM INSTR swap ;        CrossTable();        CrossTable crosstable;        crosstable;

CrossTable crosstable = new CrossTable();

Object created with Parameters

JVM INSTR new #262 <Class StringBuffer>;        JVM INSTR dup ;        JVM INSTR swap ;        String.valueOf(s2);        StringBuffer();        s.substring(j, i);        append();        s6;        append();        toString();        s2;

s2 = (new StringBuffer(String.valueOf(s2))).append(s.substring(j, i)).append(s6).toString();//s2 += s.substring(j, i) + s6;

For Loop

int k = 0;goto _L4_L8: ... k++;_L4:        if(k < as.length) goto _L8; else goto _L7

for(int k=0;k < as.length;k++) {     ... }

While Loop

String s1 = "";          goto _L1_L3:        JVM INSTR new #262 <Class StringBuffer>;        JVM INSTR dup ;        JVM INSTR swap ;        String.valueOf(s1);        StringBuffer();        _$2(resultset, s, l);        append();        toString();        s1;_L1:        if(resultset.next()) goto _L3; else goto _L2

String s1 = ""; while(resultset.next()) {  s1 = s1 + resultSetToString(resultset, s, l); }

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