JAVA.STRUCT.EXCP.GEH : Generic Exception Handler (Java)

Summary

An exception handler is used for a very generic exception type.

• When JAVA_ANALYSIS_PEDANTIC_MODE=Yes, warnings will be issued for all such exception handlers.
• When JAVA_ANALYSIS_PEDANTIC_MODE=No, warnings will not be issued for exception handlers that always rethrow the exception.

This checker controls if exception handlers might be incorrect. For instance, an exception handler with an empty body might be an unfinished snippet of code; an exception handler for a very generic exception type might end up catching too many exceptions, also some that were not meant to be caught there.

Properties

WARNING_FILTER += discard class="Generic Exception Handler (Java)"

Example

// Main.java 
import java.io.FileWriter;

public class Main {
  public static void main(String args[]) {
    FileWriter fw = null;
    try {
      fw = new FileWriter(args[0]);
      fw.close();
    }
    catch (IndexOutOfBoundsException e) {} // Empty Exception Handler (Java) warning issued here
    catch (Exception e) {                  // Generic Exception Handler (Java) warning issued here
      System.out.println("unusual");
    }
  }
}

These issues can be resolved as follows.

• Add content to the first exception handler so that it is not empty. For example, it could output a warning message to the user specifying that the program must be invoked with an argument
• Narrow the exception type caught by the second exception handler to java.io.IOException.

// Main.java, after modification 
import java.io.FileWriter;

public class Main {
  public static void main(String args[]) {
    FileWriter fw = null;
    try {
      fw = new FileWriter(args[0]);
      fw.close();
    }
    catch (IndexOutOfBoundsException e) {
      System.out.println("usage: Main filename");
    }
    catch (IOException e) {
      System.out.println("I/O error");
    }
  }
}

Resolution

Add a body to the exception handler, or narrow to the exception types.

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.

• JAVA_ANALYSIS_PEDANTIC_MODE
• REPORT_SIMILAR_WARNINGS
• WARNING_FILTER