J2se summary on the road to soft test

It took eight days to complete the j2se process. To be honest, the enthusiasm at the beginning was particularly high, and each part of the video would not be more than 30 minutes, but it was a bit impetuous at the end. This is a bad habit. Resolutely put an end to it. The following is a summary.

First, we have a macro control over j2se. Here is a one-to-one introduction!

Java basics:

Java is a cross-platform language. I will not talk about it. I only need to recognize the Java Virtual Machine and the automatic garbage processing mechanism.

Object-oriented:

Object-oriented thinking is everywhere. While learning Java, I can't help but think of the C # That I have learned #,. net is about to get the C ++ language. Teacher MI has always said that the comparison of efficiency is true, and a lot of resonance has been generated when learning this part.

1. encapsulation: hides the Implementation Details of classes and forces users to use interfaces to access data. Define the attribute as private and provide public interfaces (methods and constructors) to ensure data validity and correctness.

2. Inheritance: (1) the private attribute in the parent class cannot be directly used in the subclass. (2) Java only supports single inheritance, and a subclass has only one direct parent class. (3) override

3. Polymorphism: The method newly added to the subclass is unavailable. The parent class object can only use its own defined methods. If the method is overwritten in the subclass, the parent class calls this method and actually calls the method after rewriting.

This chapter also talked about the conversion of data types, selection of sorting, and Bubble sorting methods, which resonate with the self-developed "Introduction to Data Structure.

Java applications:

Common Java classes, string-related classes (comparison between string and stringbuffer), basic data type packaging classes, math classes, file classes, and enumeration classes. I will not go into details here.

Io stream operations, in the words of Jack Ma, are to pile up a pipe to a file. Then perform relevant operations, and the parallel importance of image thinking and logical thinking.

In the course of learning Java, I especially appreciate the memory analysis method adopted by Jack Ma. In the future, I hope everyone can master it well, just like when Learning mechanics in high school physics, stress analysis is an essential process. In addition, you must learn to query the API documentation.

J2se summary on the road to soft test