Compile a list of classes in java

I think that writing a list of classes is very popular with programmers. Should I say it is the most important? There are no strict rules. In fact, there are no rules. Class appears at the top of the mentality, lists as follows. You are welcome to join your own list. This list will work on projects of the type.

1. java. lang. string
The string class will be undisputed to the champion in any day's popularity and cannot be denied. This is the last class that is used to create an operation for the immutable string literal value.

2. java. lang. system
The usage system depends on the type of project, your work. You may not use it in your project, but it is still a popular workflow engine. This is a metadata class and cannot be instantiated. This class is used to obtain standard input, output, and environment variables.

3. java. lang. exception
Throws all errors and exceptions of the superclass. All exceptions can be handled in exceptions. Is the most popular exception. All exceptions are at the highest level.

4. java. util. arraylist
An array data structure is implemented. This class implements the list interface, which is the most popular member or collection framework. The differences and Vector Array lists are a hot topic for beginners and frequently asked questions.

5. java. util. hashmap
Implements a key-value pair data structure. This class implements the map interface. Like vector-vectors, we have a popular comparison between values and hash tables. This happens to be a popular collection class, which serves as a multi-layer application between the property value of a container and the project as a transport agent.

6. java. lang. object
Grandfather class. Each class is a class object. It will be used in a platform framework that is often used in our work. It contains important methods, equals, hash, clone, String, and so on.

7. java. lang. thread
A thread is a single execution sequence. Multiple Threads can coexist and share resources. We can expand this thread class and create our own threads. Running is another option. The usage of this class depends on the application of the domain. This is completely unnecessary to build a common application.

8. java. lang. class
Class is a direct subclass object. Is there a class loader in the Java Rapid Development Virtual Machine loaded in the constructor object of this class. Most of us may not use it directly, but I think its basic class. It is an important type of reflection.

9. java. util. date
This is used for the working date. Sometimes we feel that this class adds more practical methods and what we ultimately create. The creation date of each enterprise application is useful. I introduced a lot of methods for self-ridicule in Class 1 and later great changes in jdk1.1.

10. java. util. iterator
This is an interface. This is very popular as an alternative enumeration. It is easy to use and practical, and works in synchronization iteration.