Errors in Java Programs
1. Three Kinds (beginner — which can you catch?)
Compile-time (javac stops you: ; missing!), Runtime (JVM crashes: divide by zero!), Logical (runs, wrong answer: average bug!). Only runtime exceptions catchable!
2. Table + Examples (exam!)
// int x = 5 // COMPILE (missing ; — red underline, no .class!)
// int y = 10 / 0; // RUNTIME (ArithmeticException — crashes!)
int total = 7, n = 2;
System.out.println(total / n); // 3 (LOGICAL — runs, wrong average! need /2.0!)
| Kind | When | Fix |
|---|---|---|
| Compile (syntax/type) | javac time |
read error line, fix ;/types |
| Runtime (exception) | java run time |
try-catch (next topics!) |
| Logical | runs, wrong output | test + debug (print values!) |
3. Error vs Exception (Java words!)
Error (fatal: OutOfMemory, StackOverflow — don't catch!) vs Exception (catchable: Arithmetic, NullPointer, ArrayIndex!).
4. Beginner Workflow
Red in IDE? Compile error (fix first!). Crash with name+line? Runtime (read stack trace bottom→top for YOUR line!). Wrong number? Logical (add prints!).
5. Exam Points
- Three kinds + example each — 5 marks, very frequent.
- Error vs Exception — 3 marks, frequent.