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What is Java Static Import?
Description: |
In general, any class from same package can be called without importing it. Incase, if the class is not part of the same package,
we need to provide the import statement to access the class. We can access any static fields or methods with reference to the class name. Here comes the
use of static imports. Static imports allow us to import all static fields and methods into a class and you can access them without class name reference.
The syntax for static imports are given below:
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Code: |
package com.java2novice.staticimport;
// To access all static members of a class
import static package-name.class-name.*;
//To access specific static variable of a class
import static package-name.class-name.static-variable;
//To access specific static method of a class
import static package-name.class-name.static-method;
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Static Import Example: |
Here we have two classes. The class MyStaticMembClass has one static variable and one static method. And anther class MyStaticImportExmp
imports these two static members.
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MyStaticMembClass.java |
package com.java2novice.stat.imp.pac1;
public class MyStaticMembClass {
public static final int INCREMENT = 2;
public static int incrementNumber(int number){
return number+INCREMENT;
}
}
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MyStaticImportExmp.java |
package com.java2novice.stat.imp.pac2;
import static com.java2novice.stat.imp.pac1.MyStaticMembClass.*;
public class MyStaticImportExmp {
public static void main(String a[]){
System.out.println("Increment value: "+INCREMENT);
int count = 10;
System.out.println("Increment count: "+incrementNumber(count));
System.out.println("Increment count: "+incrementNumber(count));
}
}
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Output: |
Increment value: 2
Increment count: 12
Increment count: 12
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wait Vs sleep methods
sleep():
It is a static method on Thread class. It makes the current thread into the
"Not Runnable" state for specified amount of time. During this time, the thread
keeps the lock (monitors) it has acquired.
wait():
It is a method on Object class. It makes the current thread into the "Not Runnable"
state. Wait is called on a object, not a thread. Before calling wait() method, the
object should be synchronized, means the object should be inside synchronized block.
The call to wait() releases the acquired lock.
When I do good, I feel good; when I do bad, I feel bad, and that is my religion.
-- Abraham Lincoln
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