Java Study Notes 6 -- class inheritance, Object class, and study notes 6 --
Next, we learned the following:
Java study notes 5-Class Method
Java Study Notes 4-basic concepts of classes and objects (2)
A. class file
Note: Each class file corresponds to a unique class or interface definition information, but the class or interface is not necessarily defined in a file (for example, a class or interface can also be generated directly from the ClassLoader).
Secon
Class Loader?? The virtual machine design team takes the "fully qualified name of a class to obtain a description of this type of binary byte stream" in the class loading phase, which is implemented outside the Java Virtual machine. So that the application can decide for itself how to get the classes it needs. The code
Many people may not be familiar with the inner class mentioned in Java. In fact, similar concepts also exist in C ++, that is, nested class (nestedClass). The differences and relationships between the two are compared in the following section. On the surface, an internal class defines another
strings, dates, and numbers are the most commonly used data objects in Java programs, and the creation, modification, formatting, and transformation of these data are incorporated into every corner of the Java program and must be mastered. This section demonstrates the following common entity classes through an instance
Java System-Level classes: System
Class, abstract class, interface, inheritance and object (Java)
Zookeeper --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------This is not a teaching material. I sometimes look at it on th
This article mainly introduces the Java language class class usage and generalization (detailed), we all know that Java program in the running process, all the object type identification, that is, Rtti. This information records the class to which each object belongs. A virtu
object, the Java compiler implicitly transfers the reference of its external Class Object and keeps saving it. In this way, internal class objects can always access their external class objects. This is also why external class objects must be created before they are created
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The version number of the magic number and
When we see class, do we suddenly think of the class we wrote in the program? This class is not a class, the class is actually called the Java class collectively, we can call it abstrac
Java Class Library Concepts: Java's application Interfaces (APIs) are organized in packages, each of which provides a large number of related classes, interfaces, and exception handling classes, and the collection of these packages is the Java class LibraryThe package name begins with
One, Java provides three kinds of ClassLoader to load class:1.BootStrap ClassLoader: called the Startup class loader, is the topmost class loader in the Java class loading hierarchy, responsible for loading the core
Java object-oriented -- class loaders and reflection, java object-oriented -- LoadingThe relationship between jvm and class in the Class Loader
When you call a java command to run a java
StaticClassStatic class (Java)
In general, the class cannot be modified using static. If you must use the static modifier class, the static modifier is usually an anonymous internal class.
Create another class in a
How to update the Class in the Java package, or re-package the class in the package
The following describes how to execute basic commands:
Only the javac, jar, and java (*. exe) commands are used,
I. javac [compiling Java source files into
Up-depth Java virtual machine- - deep Java Virtual Machine (ii)--Class loader details (above), in the previous article, we explained the life cycle of the class loading and linking, this one we went on to look down. initialization of the class : initialization of a
The de jure command corresponds to a process.
When we start a Java program that starts a main method, it starts a Java virtual machine process, no matter how complex the process is. Different JVM processes do not interact with each other. This is why the Java program has only one entry--main method that allows the virtual machine to invoke. The two Mian methods,
Encapsulation: is to encapsulate some attributes and methods into a class.
Inheritance: Just as subclasses inherit some of the properties and methods of the parent class.
Polymorphism: Just as a parent class has several distinct subclasses.
Here I do not explain more, the following I mainly explain an inheritance. Inheritance is a feature of OOP (object-oriented)
The Date class _ Calendar class Java. util. Date class is an encapsulation class. If you create an object of this encapsulation class, you can get the system time, and the system time obtained is a Long data type. The data of this
From: http://klcwt.iteye.com/blog/452834
Create another class in a class called the internal class of the member. The internal class of this Member can be static (modified using the static keyword) or non-static. Static internal classes have various restrictions during definition and use. Therefore, it is not much use
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