In Jython, we can easily import a Java package like this:
Java:
package javapkg;
public class TestClassInJava {
}
Python:
from javapkg import TestClassInJava
However, if we have another package with the same name in Python:
javapkg/__init__.py:
class AnotherClassInPython:
pass
And in another Python file:
from javapkg import AnotherClassInPython # success
from javapkg import TestClassInJava # ImportError: No module named TestClassInJava
The Python package can be successfully imported, while the Java class in the same package will unable to be imported.
Is there anyway to merge these two namespace to make them both available?
Related
I am using jython interpreter programmatically (PythonInterpreter) in my java application, and I'd like to add a specific class, eg. MyJythonLib as a Jython import module so that my Jython script could have something like:
import MyJythonLib
a = MyJythonLib.getStuff()
where MyJythonLib.java is
public class MyJythonLib
{
private Object stuff;
public Object getStuff()
{
return stuff;
}
}
How do I set this class to be a module for my Jython interpreter?
Ensure MyJythonLib is in your classpath.
import MyJythonLib with reference to its fully qualified name.
For example:
import com.mycompany.MyJythonLib
Or:
from com.mycompany import MyJythonLib
Or:
import com.mycompany.MyJythonLib as MyJythonLib
Here's the code for the source file:
package moa4;
public class Book {
....
}
And for the destination file:
import moa4.Book;
public class Library {
...
}
The source and the destination are both saved in the same directory with the address:
C:\Users\\java\M\moa4
I'm getting the following error: package moa4 does not exist
You asked Library to import a package moa4.Book but you defined no such package. Instead, you defined a type Book inside package moa4, and that is not consistent with your import directive.
You could either import the package, or make that an import static of the class, but since Book and Library are both in the same package you don't need the import directive at all.
As mentioned, C:/Users/java/M needs to be in your classpath ("-cp" option).
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'm trying to declare a package in a file as follows:
import java.util.*;
package rtg;
public class Generate
{
// ...
}
But I'm getting an error when I try to compile this:
Generate.java:3: class, interface, or enum expected package rtg;
Why am I getting this error?
it should be
package rtg;
import java.util.*;
public class Generate{
}
In java you first define package then imports and then class. See wiki here: Java_package and Oracle's tutorial here: Java Packages
Edit
Now to call Genereate class from a class in same folder that is rtg folder:
package rtg;
public class GUI{
Generate gen = new Generate();
}
Make sure all words are spelled correctly.
The pacakge declaration must be the first thing in a Java file (apart from comments). You can't put the imports above it.
All the examples are above is good but we have to compile this package making class by swich standard ... You have to give "-d" and destinations folder for making package in it. "c: \f1 >javac -d e: \f2 temp . Java" 'c,e'are drive, 'f1,f2' are folder, temp is class name.