Exception handling

Division by zero

Cava throws an exception only when an int value is divided by zero. Dividing a double value by zero does not throw an exception.

Guidelines:

• Always check that a divisor is non-zero before dividing int values.

Code that throws an exception:

int b = 0;
int a = 1 / b; // Throws an exception: int division by zero

Code that does not throw an exception:

double c = 0;
double b = 1 / c; // No exception
int a = 1 / c;    // No exception

Safe pattern:

int b = 0;
int a = 0;
if (b != 0) {        // Guard against zero before dividing
    a = 1 / b;
}

Array index out of bounds

Cava throws an exception when you access an array element at a negative index or at an index equal to or greater than the array's length.

Guidelines:

• Check that the index is greater than 0 (lower limit).

• Check that the index is less than a.length (upper limit).

Code that throws an exception:

int[] a = new int[10];
a[-1]; // Throws an exception: index below lower limit (0)
a[10]; // Throws an exception: index exceeds upper limit (a.length - 1)

Safe pattern:

int[] a = new int[10];
int idx = 10;
if (idx > 0 && idx < a.length) { // Validate both bounds before access
    int b = a[idx];
}

Null pointer access

Cava throws an exception when you call a method or access a property on a null object.

Guidelines:

• Check that an object is not null before calling any method on it.

Code that throws an exception:

Person student = null; // Person is a pre-defined class
student.setAge(15);    // Throws an exception: object is null

Safe pattern:

Person student = null;
if (student != null) { // Verify the object is initialized before use
    student.setAge(15);
}

Manually throw an exception

Use Abort.abort() to stop execution immediately and signal an error from within your Cava script. Pass a message string to include error details.

Abort.abort();              // Stop execution with no message
Abort.abort("exception");   // Stop execution with an error message