The level of Java Core API needs to be mastered

Java's core API is very large, which gives developers a lot of convenience, often people have comments, Java makes programmers dull.

But some content I think is must grasp, otherwise can not skillfully use Java, also will not use "just silly". 1, under the Java.lang package of more than 80% of the functions of the flexible use of the class.

2, Java.util package of more than 80% of the flexible use of classes, especially the collection class system, regular expressions, time, attributes, and timer. 3, java.io package of more than 60% of the use of the class, understand the IO system based on the pipeline model design ideas and common IO class characteristics and use of occasions.

4, under the Java.math package of 100% content.

5, java.net under the package of more than 60% of the content, the functions of various classes are more familiar.

6, Java.text under the package of more than 60% of the content, especially the format of the class.

7, skilled use of JDBC. 8, java.security package under more than 40% of the content, if there is no contact with the security is simply impossible to master Java. 9, AWT basic content, including a variety of component events, listeners, Layout manager, common components, printing.

10, the basic content of swing, and AWT requirements similar.

11, XML processing, familiar with the pros and cons of Sax, Dom, and jdom and can use one of these to complete XML parsing and content processing.