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This noncompliant code example attempts to concatenate the string elements of array c values and store the result as the first element. It uses an ArrayIndexOutOfBoundsException to detect the end of the array and reinitialize the value of variable i to 0 in the catch block. However, if some element of the array is null, a NullPointerException results. This exception is caught and ignored, a violation of EXC15-J. Do not catch NullPointerException. Consequently, the variable i is not reinitialized to 0 in the catch block.

String cvalues[] = new String[3];
cvalues[0] = "value1";
cvalues[1] = "value2";
cvalues[2] = "value3";
	
int i;
cvalues[1] = null; // gets null value

try {
  i = 0;
  while(true) {	         
    cvalues[0] = cvalues[0].concat(cvalues[i + 1]); // Concatenate and store in cvalues[0]  
    i++;
  }
} catch (ArrayIndexOutOfBoundsException e) {
  i = 0; // Attempts to initialize i to 0
} catch (NullPointerException npe) {
  // Ignores
}

It uses an ArrayIndexOutOfBoundsException to detect the end of the array and reinitialize the value of variable i to 0 in the catch block. However, if some element of the array is null, a NullPointerException results. This exception is caught and ignored, a violation of EXC15-J. Do not catch NullPointerException. Consequently, the variable i is not reinitialized to 0 in the catch block.

The real purpose of exception handling is to detect and recover from exceptional conditions and not to willfully transfer control flow. Besides, performance wise, the exception-based idiom is far slower than the standard code block. It also prevents certain optimizations that the JVM would otherwise perform.

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String cvalues[] = new String[3];
cvalues[0] = "value1";
cvalues[1] = "value2";
cvalues[2] = "value3";

int i;
for (i = 1; i < cvalues.length; i++) {
  cvalues[0] = cvalues[0].concat(cvalues[i]);
}
i = 0; // Initialize i to 0 after operation

Risk Assessment

The use of Using exceptions for anything but detecting and handling exceptional conditions can result in performance degradation and poor design.

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