To get started, you must find a method that suits you in order to get twice the result with half the effort, and have a general understanding of the knowledge points you need to master. The basic knowledge of Java entry includes: identifiers, variables, AScii codes and Unicod codes, basic data type conversion String classes, and hexadecimals. , Operators, program flow control statements, methods, etc.
The basic knowledge points of Java entry need to be mastered:
1. Static methods and attributes
Static methods and attributes are used to describe the characteristics of a certain group of objects, rather than the characteristics of a single object. A large number of static methods and properties are used in Java. But this technique is not used frequently in many languages. Understanding static methods and properties is very helpful for understanding the relationship between classes and objects. In a large number of Java specifications, static methods and properties are frequently used. Therefore learners should understand static methods and properties. Java is consistent in calling methods and properties, and the difference is only in the declaration when it is different from C++.
Second, the interface
In the early object-oriented applications, class inheritance was used extensively, and aggregation was used instead of inheritance. The important principle of software engineering to solve scalability is abstract description, and the directly used tool is the interface. Interfaces have gradually become the core of Java programming methods in recent years. On the other hand, as far as applications are concerned, most of the development is based on specifications, and there is no need to establish complex inheritance relationships and huge classes by yourself. Understanding the specifications and using them well has become the primary task of application developers. The main description method of Java specifications is the interface.
Three, the collection framework
The main way for Java to describe complex data structures is the collection framework. Java does not have pointers, but uses a powerful collection framework to describe complex data structures such as arrays and object arrays. Learning the description methods of these data structures is very important for application programming, especially when it comes to server and three-tier structure programming. Programmers can no longer use structures such as database result sets to describe data at this time. Because many languages do not have such a powerful collection framework system, many beginners are at a loss, let alone what they are used for, which should attract enough attention.
Four, exception capture
Java's emphasis on exception capture is unprecedented, forcing programmers to describe exception capture in a significantly different way from logical methods, which is of great significance to the completeness and rigor of program description. C++ also has similar mechanisms, but we have seen that many C++ programmers are not accustomed to using these mechanisms. Beginners of Java should fully learn this external capture mechanism and develop good programming habits.
Five, multithreading
Many Java programmers are keen to write multi-threaded programs, which are considered to be a challenge to logic capabilities. In a large number of applications, there is no need to write multi-threaded programs at all, or most programmers who write application programs will not write multi-threaded programs. This is because the multi-threading mechanism is built into the basic platform. What programmers should understand is the principle of multithreading and multithreading safety, which is essential to accurately grasp the program in the future.
Six, network programming
Java is a powerful network programming language, but most application developers never develop low-level network programs by themselves and understand the principles. The realization of the network mechanism depends on the platform. Unless you develop the platform yourself, you don't need to know how the socket is implemented and how to monitor access. Too much effort in this regard deviates from the assumption that "the future application development will be developed on a mature platform, rather than developing the platform from the bottom by itself."
In the process of learning Java, we need to clarify what I need to do; analyze the ideas, how I want to do; determine the steps, which statements, methods and objects are used in each part of the idea; code implementation, use specific java language codes to understand the ideas Reflected.
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