Effective Java English Second Edition reading notes Item 7:avoid finalizers

Finalizers is Unpredictable,often Dangerous,and generally unnecessary.

Their use can cause erratic Behavior,poor performance,and portability problems.

Finalizers has a few valid Uses,which we ' ll cover later in this item,but as a rule of thumb,you should avoid finalizers.

C + + Programmers is cautioned not to think of finalizers as Java ' s analog of C + + destructors. In C++,destructors is the normal the Reclaim the resources associated with a object,a necessary counterpart to Constr Uctors. In java,the garbage collector reclaims the storage associated with a object when it becomes unreachable,requiring no spec Ial effort on the part of the programmer. C + + destructors is also used to reclaim other nonmemory resources. In java,the try-finally block are generally used for this purpose.

// try-finally block guarantees execution of termination method Foo foo=new  foo (); try{    //do-what-must be-donewit foo}finally{//provide an Explicit termination method.    // Explicit termination Method}

Explicit termination methods is typically used in combination with the try-finally construct to ensure termination.

But the finalizer should logs a warning if it finds that the resource have not been terminated.

// Finalizer Guardian Idiom class foo{    //    Final object finalizerguardian=new  object () {        Protected Ovid Finalize Thros throwable{     ... // Finalize Outer Foo Object }};     // remainder omitted}

Effective Java English Second Edition reading notes Item 7:avoid finalizers