final modifier

Puzzle the issue of inheritance. For instance methods: When naming the same, subclasses overwrite the methods of the parent class, and the access permission is at least as large as the parent class.

DataType-------------Basic data types1.2 int1.byte short int long float double2.boolean[true,false]3.char reference types1.class2.interface3.[] Function--------function, methods, methodEncapsulates the function code.Definitions cannot be nested.

1. What are thread local variables? AnswerA thread local variable is a variable that is confined to the thread itself and is owned by the thread itself and is not shared among multiple threads. Java provides the ThreadLocal class to support

1. Defining classesclass class Name { 0 to multiple constructor definitions ... 0 to multiple member variables ... 0 to multiple methods ...}1.1 Defining constructors[modifier] Constructor Name (parameter list ) {// constructor name

Depending on the context, there are subtle differences in the Java keyword final, but it usually means "this cannot be changed." "There are two reasons why you don't want to change: one is efficiency, the other is design. Because there are two

The initialization time of the classIn the previous article, we talked about six active uses of classes, one of which is reflection (class.forname ("Com.jack.test")), It is important to note that when you load a class by calling the LoadClass method

Java Interview Essentials Summary set (partial answers)DescriptionIf you're lucky enough to see it,1, the overall framework of this article from @ Ali Liang's blog, summed up very good. Worthy of our study, its blog part of the answer.2, because of

Reusing code is one of the many compelling features of Java.There are two methods for reusing a class. The first: Simply create an object of the existing class in the new class. Because the new class is made up of objects of existing classes, this

Today, the programmer's little ape and the product is about the need to happen the story. Not long ago, the little ape received the demand for the product.Product Manager: Little Ape, in order to cater to the public cock Silk User's taste, we want

Today, the programmer's little ape and the product is about the need to happen the story. Not long ago, the little ape received the demand for the product.Product Manager: Little Ape, in order to cater to the public cock Silk User's taste, we want

Object-Oriented programming learning notesI. Flexibility of correspondence-polymorphismPolymorphism means that for a service function, it can be implemented in different ways, that is, multiple forms. The polymorphic image describes the complex

Benefits of Inheritance Improve the reusability of your code. Having a relationship between classes and classes provides a precondition for a third feature polymorphism. (No inheritance, no polymorphism) Java supports single

Java learning Note Object-oriented static,final keyword i. Static keyword1. Overview:Static, statically decorated members belong to a class, do not belong to a single object, are shared by all objects, exist in a static zone, and static members take

In the previous few days of the post "Java performance optimization [1]: Basic type vs Reference type", I probably described the difference between "reference type" and "Basic type" on storage. A netizen in the comments yesterday criticized that

The previous article (Portal: Hibernate learning note _01) introduced a brief introduction to what Hibernate is, how to build it, a detailed description of the configuration file, and a few basic API details of hibernate. Then this article will take

pre-defined class loaders (three types):Start (Bootstrap) class loader:is a class loader implemented with native code that is responsible for loading the class library below /lib into memory (such as Rt.jar).Because the boot ClassLoader involves the

Immutable classes: When an instance of this class is created, the value of its member variable cannot beAdvantages:1. The value of the thread-safe object cannot be changed, reducing the likelihood of concurrency errors2. High efficiency when an

This article records the policy of ensuring concurrency security--invariance.(Note: It is immutable, not invariant!)Organizing a sequence of behaviors into an atomic operation to guarantee invariance conditions, or using a synchronization mechanism

See the old Luo Luo Shenyang's interview, can't help but admire, very young, I thought and yonghao a level of age, is also seen is not the beginning of high school programming one of the Daniel, after the interview, found that Lao Luo is also step

1Spring Transaction Propagation BehaviorThe so-called transaction propagation behavior is how transactions are propagated between these methods when multiple transactional methods are called each other. Spring supports 7 kinds of transactional