Basic Java syntax (1) ---- keywords Identifiers (Java language identifiers naming rules Java language package name, class name, Interface Name, variable name, function name, constant name naming rules), java basic syntax
I. Keywords
Keyword definition and features
Definiti
Unlike other languages, Java runs on a Java Virtual Machine (JVM ). This means that the compiled code is saved in a platform-independent format, rather than running on a specific machine. This format is significantly different from the traditional executable code format. Specifically, unlike C or C ++ programs, Java programs are not an independent executable file
Java differs from other languages in that Java is run in Java Virtual Machines (JVMS). This means that the compiled code isA platform-independent format that is saved instead of running on a particular machine. This format and the traditional canThere are many important differences in the execution of code formats. Specifically, unlike a C or C + + program,
Dark Horse programmer _ Java exception common Java Library Class, dark horse _ javaJava exception 1: Basic concepts of exceptions
Exceptions are a type of command flow that causes program interruption. They are abnormal during runtime. in Java, all exceptions follow the object-oriented design philosophy, all exceptions
Each class is compiled with a class object stored in the. class file, and the JVM uses the ClassLoader (class Loader) to load the class's bytecode file (. Class), the ClassLoader is essentially a classloader chain, in general, we only use a native ClassLoader appclassloader,
package in the Java_home/lib directory or-xbootclasspath the specified directory;(2) extention Class Loader: Loads the jar packages under the Java_home/lib/ext directory or-djava.ext.dirs the specified directory.(3) System class Loader: Loads a class or jar package under CLASSPATH or-djava.class.path specified directory.
What you need to know is:
1. In addit
Java class loader (1)-Class Loader hierarchy and ModelClass Loader
?? The virtual machine design team put the "get and describe the binary byte stream of this class through the full qualified name of a class" action in the class l
Preface:Java's library is growing and contains countless classes and interfaces. But there are some very important classes and interfaces, which are the core part of the Java class library. Common examples include string, object, class, collection, classloader.... Familiarizing yourself with these classes is the basis for learning
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)
Welcome to other blogs on this topic:
Deep Dive into Java Virtual Machine (I)-detailed explanation of the underlying structure of Java Virtual Machine
Deep Dive into Java Virtual Machine (II)-class lifecycle (I) class loading and Connection
In-depth
I learned Spring today and suddenly wanted to review the Java class loading and class reflection. Consolidate the underlying principles. Some of them refer to Teacher Li Gang's crazy Java handout and Spring3.x enterprise application development practices by Chen xionghua and Lin kaixiong. 1. A command corresponds to a
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
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
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
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
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)
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
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