Flow Control and Exception Handling - Exception Handling

• methods must declare which checked exceptions they may throw in their throws clause

public void methodName throws Exception1, Exception2,()

• you do not have to include any checked exception which will be caught and handled within the method
• a method can throw multiple exceptions
• a method can only throw exceptions that have been declared in the throws clause
• an overriding method cannot throw any checked exceptions which are not part of the original methods throws clause
• the throws clause must also include any possible exceptions that can be thrown by the method
• if you invoke a method that has a checked exception in its throws clause you can
  1. catch and handle the exception
  2. catch it and throw one of the exceptions listed in the method throws clause
  3. declare the exception in your throws clause
• a method which does not have a throws clause may still throw unchecked exceptions or errors
• these exceptions and errors can occur at any time, in any code

Standard Unchecked Exceptions:

ArithmeticException                 IllegalTrheadStateException
ArrayStoreException                 IndexOutOfBoundsException  
ClassCastException                  MissingResourceException   
EmptyStackException                 NegativeArraySizeException
IllegalArgumentException            NoSuchElementException
IllegalMonitorStateException        NullPointerException  
IllegalStateException               NumberFormatException
                   SecurityException                            
                            
Standard Unchecked Errors:

AbstractMethodError                 NoSuchFieldError
ClassFormatError                    NoSuchMethodError
ExceptionInInitializerError         OutOfMemoryError
IllegalAccessError                  StackOverflowError
IncompatibleClassChangeError        ThreadDeath
InstantiationError                  UnknownError
InternalError                       UnsatisfiedLinkError
LinkageError                        VerifyError
NoClassDefFoundError                VirtualMachineError

• Static initializers, instance initializers, and class or variable initializers must not produce any checked exceptions

• exceptions are thrown using the throw statement

throw Expression;    
throw new ExampleException(); 

• or by invoking a method that throws an exception
• the expression must be an instance of a Throwable object ie the exception class must implement Throwable