These breakpoints are assigned to the lines of source code and are used to target a particular section for debugging.
Method breakpoints act in response to the program entering or exiting a particular method. They let you target your debugging sessions by method you wish to investigate, rather than by line number. Method breakpoints let you follow the program flow at the method level as well as check entry and exit conditions. Note that using method breakpoints can slow down the application you are debugging.
Exception breakpoints are triggered when the specified exception is thrown. Unlike the line breakpoints, which require specific source references, exception breakpoints apply globally to the exception condition, rather than to a particular code reference.
Field watchpoints allow you to react to any access or modification of specific instance variables. For example, if at the end of a complicated process you are ending up with an obviously wrong value on one of your fields, then setting up a field watchpoint may be the quickest way to determine the origin of the fault.