What is the difference between "import java.lang.Integer;" and " import java.lang.Integer.*;".
I have read on internet that the Integer is a class inside the lang package. If this is true then then " import java.lang.Integer.*;" should give an compilation error because the statement " import java.lang.Integer.*;" mean to import all the classes inside the package Integer but Integer is not a package it is a class.
But both statements compile without any error.
Please clarify. Thanks a lot in advance.
If i will write "import java.lang.Integer;" so its a particular find Integer Function only.if I will write "import java.lang.Integer.*; so Its all function Included which Extension of "java.lang.integer".
import java.lang.Integer.*;
The above statement is a less common form of import, allows you to import the public nested classes of an enclosing class(in this case Integer class).
Consider for example, if the graphics.Rectangle class contained useful nested classes, such as Rectangle.DoubleWide and Rectangle.Square, you could import Rectangle and its nested classes by using the following two statements.
import graphics.Rectangle;
import graphics.Rectangle.*;
Be aware that the second import statement will not import Rectangle.
Related
I have this class that I want to import into another class that is outside the previous class folder.
So, I have a GoogleDriveAPI class, which I want to import to DocumentServices class.
on top of my GoogleDriveAPI class there is this line
package org.ofbiz.ClientManagementServices;
but when I try to import it to DocumentServices class with this line below
import org.ofbiz.clientmanagementservices.GoogleDriveAPI;
I get this error below,
error: package org.ofbiz.clientmanagementservices does not exist
[javac17] import org.ofbiz.clientmanagementservices.GoogleDriveAPI;
What might be the problem with my import because I am 100% sure I am doing the right thing?
Java packages are cas sensitive.
You should change the import to :
import org.ofbiz.ClientManagementServices.GoogleDriveAPI;
I have several java files in a package and all of them have the same import blocks e.g :
package org.ezim.core;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import org.ezim.core.Ezim;
import org.ezim.core.EzimDtxSemantics;
import org.ezim.core.EzimLogger;
import org.ezim.ui.EzimFileOut;
import org.ezim.ui.EzimMain;
It looks awful having the same batches of code in each file and i want to refactor it.
I was wondering if its possible to put all these imports in a single java file then use a single line in all the other java files to call them.
Its like the extend function for classes (for variables) , but i want one for the imports.
Thanks
No. That isn't possible. What is possible is not using imports at all, instead you can use fully qualified class names like
org.ezim.core.Ezim ezim = new org.ezim.core.Ezim(); // <-- not import needed.
You can always use * sign to import multiple classes from one package, but thus watch for name clashes.
I am new in using eclipse java using multiple .java files. My eclipse java project consist of one project file two package files, each with one .java class
My 2nd java class import the 1st java class/package, like so
VerifyLogin.java
package VerifyLogin;
import ArgumentCountException;
ArgumentCountException.java
// ...
The problem is VerifyLogin.java is getting an error
Import ArgumentCountException cannot be resolved
Or any reference I have to ArgumentCountException cannot be resolved to a type.
In java if you need to import a class then you need to use the full qualified name for that class, as the following:
import packageName.YourClass;
For Example, if your need to use Scanner class, then you need to import it as:
import java.util.Scanner;
But if the class was withing the same package, you don't need to import it.
When importing your class, it should be done as below:
//Current package name for the VerifyLogin Class (All package names should be lowercase by convention)
package packageforcurrentclass;
//Import statements: import thedependencyclasspackage.thedependencyclassname
import exceptionpackage.ArgumentCountException;
public class VerifyLogin
{
...
}
I am using one .java file and i have given a package name as com.onlinmebank but netbeans displaying error at this package declaration line as Incorrect Package.
Following is the package declaration code.
package com.onlinebank;
import java.sql.*;
import java.util.*;
public class BankCommons{
//All Code Here
}
Can Anybody tell me why i am getting this error
All Java keywords are lower-case!
So, this should work:
package com.onlinebank;
import java.sql.*;
import java.util.*;
public class BankCommons {
//All Code Here
}
And keep in mind, that the file BankCommons.java must be placed in the directory com/onlinebank.
In package, p should be small not Package(no captial P).
Also in public class p should be small. Similarily for Import also.
Important note all java keywords are in lower cases
I am trying trying to import java.lang.Math in Java on Eclipse and am getting the error in the title. Here is the beginning of my code:
import java.lang.Math;
package test1;
This error is popping up under "package test1;"
The package statement must be first in the file, before anything, even imports:
package hw1;
import java.lang.Math;
Plus, you don't need to import java.lang.Math, or anything in java.lang for that matter.
The JLS, Chapter 7 says:
A compilation unit automatically has access to all types declared in
its package and also automatically imports all of the public types
declared in the predefined package java.lang.
Place the package declaration before the import statement
package hw1;
import java.lang.Math;
The import statement itself is unnecesary as all classes in java.lang are imported by default.
Read Creating a Package