Errors, exceptions and debugging

Question 1

Three main types of errors

Answer 1

Syntax
Runtime
Logic

Question 2

How are syntax errors checked

Answer 2

Java compiler checks syntax before generating bytecode. If there are any syntax errors the bytecode is not generated and compiler tries to identify error

Question 3

Syntax error examples

Answer 3

• Capital letters
• Incompatible type assignments
• Missing semicolon, brackets
• Using variable without declaration or initialisation
• Using a class/function not in language without import
• Missing operator/operand in expression

Question 4

Exception/run time errors

Answer 4

Occurs during execution of program and if not handled can crash the program

Question 5

exception/run time error examples

Answer 5

• division of 0
• method call to take integer input but double or char is entered
• accessing array beyond limit
• trying to read a file where file does not exist

Question 6

Logical error

Answer 6

• Most difficult to detect
• Program works but gives unexpected results