Which specific line number is causing the error?

When debugging a runtime error, the first step is to locate the exact line where the exception occurs. In most IDEs, the stack trace points to the file and line number. If the stack trace is ambiguous, add logging or use a debugger to set breakpoints around the suspected area. Once you identify the line, examine the variables and state at that point. Common causes include null references, type mismatches, or out‑of‑range indices. After isolating the issue, you can apply a fix—such as adding a null check, correcting the logic, or adjusting the data type. Finally, run the test suite to confirm the error is resolved and that no new regressions were introduced. This systematic approach—trace, inspect, fix, verify—ensures reliable debugging and maintains code quality.