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How to implement serialization in java

To implement serialization in java, you need to have a class implement the Serializable interface. This interface is an identifying interface that marks the object of this class as being serializable. Then use an output stream to construct an object output stream and pass writeObject(Object obj) method can write out the implementation object.

Nov 14, 2019 am 11:47 AM

java

Java project jsp error report

Solution to jsp error in java project: 1. Add the relevant dependencies of javax.servlet in the pom.xml configuration file; 2. Right-click the build path of the project to find Server Runtime, select a server lib, and click OK.

Nov 14, 2019 am 11:25 AM

java jsp Report an error

The difference between js this and java

The difference between this in js and this in java is: this in js points to whoever called the function, and this in the function points to the window by default; this in java represents a reference to the current object, that is, it points to the new object itself.

Nov 14, 2019 am 11:14 AM

java js this

How to write java in linux

How to write java in linux: 1. Download the appropriate linux version jdk; 2. Create the /usr/java directory and unzip the jdk; 3. Modify the /etc/profile configuration environment variable; 4. Use vim to write java code; 5. Use javac compiles and runs using the java command.

Nov 14, 2019 am 10:54 AM

java linux

Is then a java keyword?

Then is not a keyword in Java, nor is it a reserved word in Java. then is a keyword in other programming languages, such as the scripting language shell and Microsoft's Visual Basic language.

Nov 14, 2019 am 10:37 AM

then Keywords

How to set path in java?

How to set the path for java: First, right-click My Computer-Properties-Advanced-Environment Variables-System Variables; then select "New" in the system variable option; then add the java bin path to the path.

Nov 14, 2019 am 10:31 AM

java

What should I do if the system cannot find java?

The solution to the problem that the system cannot find java: First find the jdk directory and copy the jdk top-level directory; then open the system properties and select the system environment variable settings; then add a system variable "JAVA_HOME" and paste the jdk directory.

Nov 14, 2019 am 10:19 AM

java

What are java collections

There are two major categories of Java collections: List and Set, both of which implement the Collection interface. List includes ArrayList, Vector and LinkedList; Set includes HashSet and TreeSet.

Nov 14, 2019 am 10:10 AM

java list set gather

java mutable classes and immutable classes

A Java mutable class means that after obtaining an instance of this class, the content of the instance can be changed, such as changing the internal member variables of this instance; an immutable class means that after obtaining an instance of this class, the contents of the instance cannot be changed. Once an immutable instance Once created, the values ??of its internal member variables cannot be changed.

Nov 14, 2019 am 09:54 AM

java Immutable Class

Solve the problem that the browser does not support java

Solution to the problem that the browser does not support Java: 1. Click on the browser settings option; 2. Click on the Internet options; 3. Click on the security option; 4. Click on the custom level; 5. Find "java applet script" and click "Enable" That’s it.

Nov 14, 2019 am 09:40 AM

java

Java determines whether a variable is empty

How to determine whether a variable is empty in java: first import the org.springframework.util package; then use "StringUtils.isEmpty(Object str);" to determine; finally, you can determine that the variable is empty based on the returned value being false.

Nov 14, 2019 am 09:32 AM

java

Java determines whether an array contains a certain value

How to determine whether an array contains a certain value in Java: 1. Create a findStr function and pass in two parameters: the array and the value to be found; 2. Use a for loop within the function to traverse the array; 3. Use equals to determine whether the array element is There are elements that are the same as the value to be found; 4. If there are the same elements, the array contains this value.

Nov 14, 2019 am 09:20 AM

java judgment array

What are the basic interfaces of Java collection class framework?

The basic interfaces of the Java collection class framework have two major interfaces: Collection and Map, one is a collection of elements and the other is a collection of key-value pairs; among them, the List and Set interfaces inherit the Collection interface; HashMap and HashTable implement the Map interface.

Nov 14, 2019 am 09:08 AM

java

what is java expression

A Java expression is a combination of variables or constants and symbols, ending with a semicolon ";". The main categories of Java expressions include arithmetic expressions, assignment expressions, conditional expressions and logical expressions.

Nov 13, 2019 pm 05:37 PM

java expression