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Check what java version is

The method to check the java version is: first open the computer desktop, use the shortcut key [win+R] to enter cmd to bring up the window; then enter [java -version] in the window; finally press Enter to view the version.

Jul 04, 2020 pm 03:10 PM

java

What does extends mean in java

The role of extends in Java is to inherit. In Java, an existing class is inherited through the keyword extends. The inherited class is called the parent class [super class, base class], and the new class is called a subclass [ Derived classes], and multiple inheritance is not allowed in Java.

Jul 03, 2020 pm 05:57 PM

extends

What is the function of finalize method in java

The finalize method in java is a method provided in the Object class. Before the GC is ready to release the memory space occupied by the object, it will first call the finalize() method.

Jul 03, 2020 pm 03:34 PM

java

What are the formats for defining arrays in java?

The formats for defining arrays in Java are: 1. [int[] arr = new int[5]]; 2. [int[] arr = new int[]{1,2,3,4,5}]. In the Java language, the length (the number of elements in the array) cannot be specified when declaring an array.

Jul 03, 2020 pm 02:50 PM

java array Format

What is the difference between hashcode and equals?

The difference between hashcode and equals is: 1. If equals of two objects returns true, hashCode must also return the same int number; 2. If hashCode of two objects returns the same int number, equals does not necessarily return true.

Jul 03, 2020 am 11:59 AM

equals hashcode

Talk about serialization and deserialization in Java objects

The concepts of serialization and deserialization: The process of converting an object into a byte sequence is called serialization of the object. The process of restoring a sequence of bytes into an object is called deserialization of the object.

Jul 03, 2020 am 10:03 AM

java object Deserialization Serialization

Can a java class have multiple parent classes?

A Java class cannot have multiple parent classes, but only one parent class. Java classes only support single inheritance and do not support multiple inheritance, so they can only have one parent class; interfaces can have multiple inheritance, so interfaces can have multiple parent classes.

Jul 03, 2020 am 09:39 AM

java

What are the eight basic data types in java

The eight basic data types of Java are: 1. Integer type, byte, int, short, long; 2. Floating point type, float, double; 3. Boolean type, boolean; 4. Character type, char.

Jul 02, 2020 pm 03:12 PM

java

What to do if a red cross appears when importing a project in eclipse

The solution to the red cross when importing a project in eclipse: First, right-click the project name and select [Configure Build Path] in [Build Path]; then select remove in Libraries; and finally add the JRE environment.

Jul 02, 2020 pm 01:29 PM

eclipse

The use of 5 commonly used annotations in springmvc

There are five common annotations in springmvc: 1. @RequestMapping, which is an annotation used to process request address mapping; 2. @RequestParam, which is used to map the request parameter area data to the parameters of the function processing method; 3. @PathVariable, used Yu will request variables.

Jul 01, 2020 pm 05:25 PM

springmvc

What is java a programming language for?

Java language is an object-oriented programming language. Object-oriented is a method of understanding and abstracting the real world. It is the product of the development of computer programming technology to a certain stage. The object-oriented development model is more conducive to people's thinking, and facilitates the division of programs during the specific development process. Division of labor and cooperation among employees to improve development efficiency.

Jul 01, 2020 pm 03:34 PM

java programming language

what is springboot

Spring Boot is a new framework provided by the Pivotal team. It is designed to simplify the initial construction and development process of new Spring applications. The framework uses a specific method for configuration, so that developers no longer need to define boilerplate configuration.

Jul 01, 2020 pm 03:32 PM

springboot

What are the three major characteristics of the Java language?

The three major characteristics of the Java language are: encapsulation, inheritance, and polymorphism. Encapsulation is to hide the information of a class inside the class, and does not allow external programs to directly access it. Instead, the hidden information is operated and accessed through the methods of the class; inheritance is a relationship between classes, more like subordinates in a collection. Regarding relationships; polymorphism refers to the multiple forms of objects.

Jul 01, 2020 pm 03:26 PM

java Features language

The difference between springboot and springmvc

The difference between springboot and springmvc is that springboot is just a configuration tool, integration tool, and auxiliary tool, while springmvc is the framework and the actual code running in the project.

Jul 01, 2020 pm 03:09 PM

springboot springmvc