package net.java.stun4j does not exist - java

I am trying to create a sip protocol handler. I am facing some difficulties to create this. I am trying to use stun4j but i can not import it. Whenever I import it shows an error package java.net.stun4j does not exist.
import net.java.stun4j.StunAddress;
import net.java.stun4j.client.NetworkConfigurationDiscoveryProcess;
import net.java.stun4j.client.StunDiscoveryReport;
I have tried different library jar files but it is always showing error. I have used java sip api. But import is always showing error. If I have to get rid of this error, what jar file should I use?

You should put jar files to your classpath.

Related

getting a import cannot be resolved error for import org.apache.http.client.methods.HttpGet

Im using eclipse Photon. The code worcked fine on old computer. When I got a new computer and tried to run the program The following imports are give me a import cannot be resolved error
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
I'm assuming im missing some jar files. Could some one tell me what jar files I need and whare i can find them? Also why does it work find on ole computer with same jars being added?
Those two classes are part of Apache HTTP Components which you can access from https://hc.apache.org/index.html.

Eclipse cannot import import com.google.maps.* (For java Fx programme)

I am working on a Java fx application and I need to import some libraries from com.google.maps.
I imported these libraries :
import com.google.maps.GeoApiContext;
import com.google.maps.PlaceDetailsRequest;
import com.google.maps.PlacesApi;
import com.google.maps.QueryAutocompleteRequest;
import com.google.maps.errors.ApiException;
import com.google.maps.model.AddressComponent;
import com.google.maps.model.AddressComponentType;
import com.google.maps.model.AutocompletePrediction;
import com.google.maps.model.PlaceDetails;
The java import statement is a little bit misnamed, it really means alias. import com.google.maps.GeoApiContext; really just means: Any time you find the type GeoApiContext anywhere in this source file, assume I meant to write com.google.maps.GeoApiContext.
Crucially, it does not 'invoke' any code in that class whatsoever, nor does it find or download any dependencies from the internet for you.
You will need to find the jar(s) that provide these classes and put them on the classpath of this project.
It can be as simple as downloading the relevant jar (perhaps com.google.maps-google-maps-services.jar?), put it in a lib dir someplace inside this project, finding that in the package explorer, right clicking it, and selecting 'add to classpath'.
Or, more likely, you want to use gradle or maven to take care of this for you: These tools turn simply mentioning the dependency in a list of libraries you require into automatically finding that on the internet, downloading it, configuring your IDE so that it knows where it is, and using that dependency during build and run steps.

Should I download a library to import com.sun.pdfview.*?

When i decided to import com.sun.pdfview.* to my program it marked an error where it specified that I should create a package for it but when I did it still gave me an error, should I download a library to be able to use it? Which one?
ps.Im using eclipse as my IDE

Do classes you import in java have to be saved already in separate files?

I have to write an extension code and am confused. Here's what I have:
import info.gridworld.actor.Bug
public class ZBug extends Bug
With the rest my code below that. I keep getting an error message saying that "the import info cannot be resolved" I'm not sure what I'm doing wrong
You are missing a semicolon at the very least:
import info.gridworld.actor.Bug;
Then, you may miss some of the dependencies.
Make sure that the info.gridworld.actor.Bug class or the JAR which contains it is in the project's build path.
If it is a Maven project, make sure to include the required <dependency>.

Import custom java file

I'm currently trying to read some source code in Java I found online to study and learn the material. I want to compile the files first to make sure they work before I study it. When I try to compile though, the compiler complains that it can't find some of the files it needs to import. So opening up the main.java, I find
package br.com.seimos.minijava;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.ArrayList;
import br.com.seimos.minijava.parser.MiniJavaParser;
import br.com.seimos.minijava.syntaxtree.Program;
import br.com.seimos.minijava.visitor.TreeDumper;
import br.com.seimos.minijava.visitor.TreeFormatter;
The errors I'm getting are coming from not being able to find MiniJavaParser, TreeDumper...the 3rd chunk of code. Those files exist in the same directory as the main file though, so what is going on? What is br.com.seimos.minijava stuff? I tried putting the files in that those folders (as in br\com\seimos\minijava\PUT_FILES_HERE) but still no good. Does br need to be in the root directory?
Thanks, I realize this is probably a really elementary question...
The required directory structure is br/com/seimos/minijava/OTHER_FOLDERS/SOURCE_FILES.java. For instance, the path to MiniJavaParser should be br/com/seimos/minijava/parser/MiniJavaParser.java. You should then run the Java compiler from the parent directory of br.
If you're using Eclipse or another IDE, you should configure your project settings to handle this.
For import br.com.seimos.minijava.parser.MiniJavaParser; your MiniJavaParser class must be in the directory br\com\seimos\minijava\parser\ and not br\com\seimos\minijava\. Similarly for other classes. Try changing it.
You're on the right track. You will need to put those files in br/com/seimos/minijava/... as indicated by the package name of each. Java requires that you put files in a directory hierarchy that matches their package names.
Then, you'll want to compile using a command like:
javac br/com/seimos/minijava/parser/MiniJavaParser.java
This is all a bit inconvenient from the command line, especially for a larger project, so you might be better of getting a Java IDE and having it help you arrange the files.

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