pxb1988/dex2jar · error · NoSuchMethodException

can't find method

Error message

can't find method 

What it means

During setup DecryptStringCmd resolves each configured method (owner/name/desc) on the loaded classes to a reflective java.lang.reflect.Method, walking up the class hierarchy. If no matching method exists it throws NoSuchMethodException naming the missing member.

Solutions

1. Verify the method name and descriptor in the config match the actual jar (use javap -p)
2. Confirm the owner class exists in the input jar and isn't obfuscated/renamed
3. Include dependency jars so parent classes can be loaded when the method is inherited
4. Fix the config line's name/desc to the real signature

Example fix

// before (config)
Lcom/foo/Bar;->decrypt(Ljava/lang/String;)Ljava/lang/String;
// after (matching real signature via javap)
Lcom/foo/Bar;->a(Ljava/lang/String;)Ljava/lang/String;

// Pre-check via reflection before configuring
Class<?> c = Class.forName(owner.replace('/', '.'), false, loader);
boolean found = java.util.Arrays.stream(c.getMethods()).anyMatch(m -> m.getName().equals(name) && Type.getMethodDescriptor(m).equals(desc));

try { setupConfigs(configs); } catch (NoSuchMethodException e) { log.error("Config points to missing method: " + e.getMessage()); configErrorExit(); }

When it happens

Trigger: A config entry's owner class doesn't contain (nor inherit) a method with exactly the configured name and descriptor — e.g. the class is missing from the jar, obfuscated/renamed, or the descriptor typo'd.

Common situations: Pointing the tool at an obfuscated APK jar where method names were renamed, or targeting a method from a library dependency not present in the scanned classpath.

Related errors

• Can't read line:

AI-assisted analysis of pxb1988/dex2jar@b5bda4fb49 (2026-09-08). Data as JSON: /api/errors/ebbda09460836478. Report an issue: GitHub.

Appendix: source

Thrown at dex-tools/src/main/java/com/googlecode/dex2jar/tools/DecryptStringCmd.java:835

        for (MethodConfig config : methodConfigs) {
            Method jmethod;
            try {
                Class<?> clz = cl.loadClass(config.owner.replace('/', '.'));
                if (clz == null) {
                    System.err.println("clz is null:" + config.owner);
                }
                jmethod = findAnyMethodMatch(clz, config.name,
                        toJavaType(Type.getArgumentTypes(config.desc)));
            } catch (Exception ex) {
                System.err.println("can't load method: L" + config.owner + ";->" + config.name + config.desc);
                throw ex;
            }
            if (jmethod != null) {
                jmethod.setAccessible(true);
                config.jmethod = jmethod;
                map.put(config, config);
            } else {
                throw new NoSuchMethodException("can't find method " + config.name + config.desc + " on class " + config.owner + " or its parent");
            }
        }
        return map;
    }

    /**
     * collect methods from --methods and --method-owner,--method-name
     *
     * @return
     * @throws IOException
     */
    private List<MethodConfig> collectMethodConfigs() throws IOException {
        List<MethodConfig> methodConfigs = new ArrayList<>();
        if (this.method != null) {
            for (String line : Files.readAllLines(this.method, StandardCharsets.UTF_8)) {
                if (line.length() == 0 || line.startsWith("#")) {
                    continue;
                }

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