pxb1988/dex2jar · error · RuntimeException

Can't read line:

Error message

Can't read line:

What it means

DecryptStringCmd.build() parses config lines of the form `Lowner;->name(desc)ret`. If the line contains no `->` separator it cannot be parsed as a method reference, so it throws this RuntimeException.

Solutions

1. Fix the offending line to use the `owner->name(descriptor)ReturnType` format
2. Strip comments/blank lines from the config file before passing it
3. Example valid line: Lcom/foo/Bar;->decrypt(Ljava/lang/String;)Ljava/lang/String;

Example fix

// before
com.foo.Bar.decrypt(java.lang.String)
// after
Lcom/foo/Bar;->decrypt(Ljava/lang/String;)Ljava/lang/String;

boolean validLine = line.contains("->") && line.indexOf('(', line.indexOf("->")) > 0;
if (!validLine) skipOrLog(line);

try { MethodConfig c = build(line); } catch (RuntimeException e) { if (e.getMessage().startsWith("Can't read line:")) { log.warn("Skipping malformed config line: " + line); } else throw e; }

When it happens

Trigger: A config line (from -c/--config file or built from -t/--arg-types input) missing the `->` separator, e.g. a blank-ish, commented, or free-form line fed to the config parser.

Common situations: Malformed lines in a method-config file (trailing comments, using `.` instead of `->`, blank lines with stray characters).

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• can't convert [ ] to type
• ERROR: Unrecognized option
• ERROR: Option need an argument value
• can't find method

AI-assisted analysis of pxb1988/dex2jar@b5bda4fb49 (2026-09-08). Data as JSON: /api/errors/250e4298f6697fe6. Report an issue: GitHub.

Appendix: source

Thrown at dex-tools/src/main/java/com/googlecode/dex2jar/tools/DecryptStringCmd.java:127

                return false;
            if (name == null) {
                if (other.name != null)
                    return false;
            } else if (!name.equals(other.name))
                return false;
            if (owner == null) {
                if (other.owner != null)
                    return false;
            } else if (!owner.equals(other.owner))
                return false;
            return true;
        }
    }

    MethodConfig build(String line) {
        int idx = line.indexOf("->");
        if (idx < 0) {
            throw new RuntimeException("Can't read line:" + line);
        }
        String owner = line.substring(0, idx);

        if (owner.startsWith("L") && owner.endsWith(";")) {
            owner = owner.substring(1, owner.length() - 1);
        }

        int idx2 = line.indexOf('(', idx);
        if (idx2 < 0) {
            throw new RuntimeException("Can't read line:" + line);
        }

        String name = line.substring(idx + 2, idx2);

        String desc = line.substring(idx2);
        if (desc.endsWith(")")) {
            desc = desc + "Ljava/lang/String;";
        }

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