pxb1988/dex2jar · error · RuntimeException

not support

Error message

not support

What it means

DvmFrame.execute interprets Dalvik opcodes on a virtual frame. When it meets an opcode it has no case for in its switch, it throws RuntimeException('not support ' + op). It means the interpreter model in this analysis API does not implement that Dalvik instruction.

Solutions

  1. Upgrade dex2jar to a version whose DvmFrame covers the opcode
  2. Add a case in DvmFrame.execute implementing the missing opcode (often a no-op setTmp for analysis purposes)
  3. Restrict analysis to methods/DEX with a supported minSdk version
  4. Catch RuntimeException around execute to skip unsupported instructions

Example fix

// before
default:
    throw new RuntimeException("not support " + insn.op);
// after
default:
    LOG.warn("unhandled opcode in DvmFrame: " + insn.op);
    setTmp(null);
    break;
Defensive patterns

Strategy: try-catch

Validate before calling

// pre-scan method instructions for opcodes known to be unsupported
Set<String> unsupported = scanForOpcodesOutsideDvmFrameSwitch(method);

Try / catch

try {
    frame.execute(insn);
} catch (RuntimeException e) {
    if (e.getMessage() == null || !e.getMessage().startsWith("not support ")) throw e;
    LOG.warn("skipping unsupported opcode " + e.getMessage().substring(12));
}

Prevention

When it happens

Trigger: Executing a DexOpcode in DvmFrame.execute whose opcode is not one of the handled cases (e.g. newer/unusual instructions like invoke-custom/range variants, packed opcodes) reaching the default branch.

Common situations: Analyzing DEX built with newer Android toolchains (API level 26+ opcodes) against an older dex2jar version; running VM-level analysis over obfuscated code containing odd opcodes.

Related errors

AI-assisted analysis of pxb1988/dex2jar@b5bda4fb49 (2026-09-08). Data as JSON: /api/errors/82708d39ea5305bb. Report an issue: GitHub.

Appendix: source

Thrown at dex-reader-api/src/main/java/com/googlecode/d2j/node/analysis/DvmFrame.java:383

            case SHR_INT_LIT8:
            case USHR_INT_LIT8:
                Stmt2R1NNode stmt2R1NNode = (Stmt2R1NNode) insn;
                setReg(stmt2R1NNode.distReg, interpreter.unaryOperation(insn, getReg(stmt2R1NNode.srcReg)));
                setTmp(null);
                break;
            case FILL_ARRAY_DATA:
                interpreter.unaryOperation(insn,getReg(((FillArrayDataStmtNode)insn).ra));
                setTmp(null);
                break;
            case GOTO:
            case GOTO_16:
            case GOTO_32:
            case RETURN_VOID:
            case BAD_OP:
                setTmp(null);
                break;
            default:
                throw new RuntimeException("not support " + insn.op);
        }
    }

    public V getTmp() {
        return tmp;
    }

    public void setTmp(V v) {
        this.tmp = v;
    }

    public V getReg(int b) {
        if (b > values.length || b < 0) {
            return null;
        }
        return values[b];
    }

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