Java Foundation Blind Spot Grooming

• The basic members of the class have default values

• Finalize () is not a destructor, there is no destructor in Java, and using Finalize () is usually a cross-language call scenario: for example, after malloc memory allocation with C, you need to do free in the Finalize () method to provide a way to release memory. Otherwise the equivalent will reach a certain level, resulting in an out of memories. The JVM will first invoke Finalize () when it performs the GC, but this does not mean that the object specified in Finalize will be released because the GC will eventually only be memory-related and garbage collected when the memory reaches the recycle condition

• static block Static{xxx;} Initializes when the class loads, non-static blocks and constructors are initialized or called when the object is created, and non-static blocks take precedence over constructors.

• Inner classes can access all members of the perimeter class, including private members

• "Multiple inheritance" can be implemented in disguise through inner classes

• Anonymous inner classes are commonly used for instance initialization

• Dynamic proxies, which dynamically create proxy,proxy by reflection, are used to add some additional actions you want to make to target, and then forward the request to target at the appropriate time. In other words, the proxy has a layer of encapsulation modification on target.

• HashMap, adjust the performance of the container by setting the capacity and load factor. When the default capacity reaches Three-fourths full, it will automatically expand & re-hash. Therefore, if you can estimate the storage capacity and then set an appropriate initial capacity, you can avoid the overhead of auto-hashing

• Transient keywords to avoid serialization of sensitive information fields

• Threadlocal objects are usually stored as static domains, so that each individual thread is assigned its own storage

Java Foundation Blind Spot Grooming