Quick fix

To see the correction proposals use the Quick Fix action

Set the cursor inside the highlight range, and select Quick Fix from the Edit menu or the context menu.
Set the cursor inside the highlight range, and press CTRL + 1
Click on the light pulp

Note that the light bulb is only a hint. It is possible that even with the light bulb shown, it turns out that no corrections can be offered.

Offered corrections
Problem	Correction Proposals
Unresolved method reference	Change to a method with a similar name Create method
Unresolved variable name	Change to a variable with a similar name Create field Create local variable Create parameter
Unresolved type name	Change to a type with a similar name Create class Create interface Add import statement
Undefined constructor	Create constructor
Parameter mismatch	Change method name to matching method
Unhandled exception	Add try / catch statement Add throws declaration to enclosing method
Type name does not match compilation unit name	Change type name Change file name
Package declaration does not match file location	Change package declaration Move file
Unused import	Remove import
Type mismatch	Add cast statement Change declared type
Unterminated string	Terminate string
Non-Externalized string	Open Externalize String wizard

To enable / disable problem indication & the light bulb go to the Java Editor preference page > Problem Indications