There are two ways to evaluate a variable when a program stops
running at a breakpoint or step.
- Option 1: Enter EVAL VariableName on the debug command
line.
- Option 2: Put the cursor on the variable name in the displayed source
code and press F11 (Display variable).
Use the EVAL command for evaluating variables in a Java™ program.
When
looking at variables in a Java program, note the following:
- If you evaluate a variable that is an instance of a Java class,
the first line of the display shows what kind of object it is. It also shows
an identifier for the object. Following the first display line, the contents
of each field in the object displays. If the variable is null, the first line
of the display indicates that it is null. Asterisks show the contents of each
field (of a null object).
- If you evaluate a variable that is a Java string object, the contents of that
string displays. If the string is null, then null displays.
- You cannot change a variable that is a string.
- If you evaluate a variable that is an array, 'ARR' displays followed by
an identifier for that array. You can evaluate elements of the array by using
a subscript of the variable name. If the array is null, then null displays.
- You cannot change a variable that is an array. You can change an element
of an array if it is not an array of strings or objects.
- For variables that are arrays, you can specify arrayname.length to see
how many elements are in the array.
- If you want to see the contents of a variable that is a field of a class,
you can specify classvariable.fieldname.
- If you try to evaluate a variable before it has been initialized, one
of two things can happen. Either a Variable not available to display message
is shown, or the uninitialized contents of the variable are shown, which could
be a strange value.