In Java, finalize()a method is defined in java.lang.Objecta class. It is called a "finalizer" and is used to perform specific cleanup operations before the object is garbage collected.
finalize()The role of the method:
- Clear resources: You can use
finalize()methods to release some resources held by the object, such as closing files, releasing network connections, and so on. Necessary resource cleanup can be performed before the object is recycled to avoid resource leaks. - Perform outstanding operations:
finalize()methods can be used to perform some outstanding operations, such as canceling outstanding tasks or returning transactions.
Although finalize()methods provide an opportunity to perform cleanup operations before an object is garbage collected, it is not a reliable mechanism. Here are some things to look out for:
- It is not recommended to rely too much on
finalize()methods: because the timing of garbage collection is indeterminate, there is no guaranteefinalize()when the method will be called. Therefore, important resource release operations should be performed through explicit code, rather than relying on the finalize() method. - The execution of the finalize() method is expensive: since
finalize()the method call is handled by the garbage collector and may cause the object to re-live, its execution introduces performance and memory overhead. In modern Java versions, it is recommended to use other mechanisms for resource cleanup, such as usingtry-with-resourcesstatement blocks to automatically close resources.
finalize()method is used in Java to perform cleanup operations before objects are garbage collected, but it is not a strongly recommended or reliable mechanism, and it is better to do resource cleanup explicitly by other means.