Supporting Material

Eclipse Support for Diagnosing Errors

• Mouse over any red error symbol that appears in the left-hand ribbon and a call-out will appear. Here's an example:

Common Syntactic Errors

• Missing or incorrect tokens, such as ; } )
• Incorrect symbol used for desired operator, e.g., using equality operator (==) incorrectly in the place of the assignment operator (=) or using wrong symbols for arithmetic addition, multiplication

Common Semantic Errors

• Attempting to use an identifier that cannot be resolved to a variable
• Attempting to use a variable before it has been declared
• Attempting to use a variable before it has been assigned an initial value
• Attempting to assign a value to a variable that has an incompatible type (see sec 1.3.3 for full description and discussion)
• Attempting to perform a type conversion (using manual casting) that is illegal (e.g., can't cast a boolean to an int)

DEFINITION OF "CORRECT"

• An app is correct if the app does what it says it will do
• An app states what it does in its external documentation (e.g., in its API or in the comments that appear before the class header)

Tools for Generating Documentation

• Examine the "doc" folder in the project and double-click on the index.html file. Notice how the contents are generated from the comments that appear before the class header! The tool that accomplishes this is called javadoc