Exceptions are divided into three categories. That are checked exceptions, runtime or unchecked exceptions and errors.

• A checked exception is an unacceptable condition foreseen by the author of a method, but outside the immediate control of the code.
• FileNotFoundException is a checked exception. This exceptions is thrown if the file that the code is trying to access can't be found.
• If a method calls another method that may throw a checked exception, either it must be enclosed within a try-catchblock or the method should declare this exception to be thrown in its method signature.

The continuestatement is used to skip the remaining steps in the current iteration and start with the next loop iteration.

• An object's lifecycle starts when it's initialized and lasts until it goes out of scope or is no longer referenced by a variable.
• When an object is alive, it can be referenced by a variable and other classes can use it by calling its methods and accessing its variables.
• Declaring a reference object variable isn't the same as creating an object.
• An object is marked as eligible for garbage collection when it can no longer be accessed.
• we can be sure only about whether objects are marked for garbage collection. we can never be sure about whether an object has been garbage collected.