Ошибка package does not exist

Are they in the right subdirectories?

If you put /usr/share/stuff on the class path, files defined with package org.name should be in /usr/share/stuff/org/name.

EDIT: If you don’t already know this, you should probably read this doc about understanding classpath.

EDIT 2: Sorry, I hadn’t realised you were talking of Java source files in /usr/share/stuff. Not only they need to be in the appropriate sub-directory, but you need to compile them. The .java files don’t need to be on the classpath, but on the source path. (The generated .class files need to be on the classpath.)

You might get away with compiling them if they’re not under the right directory structure, but they should be, or it will generate warnings at least. The generated class files will be in the right subdirectories (wherever you’ve specified -d if you have).

You should use something like javac -sourcepath .:/usr/share/stuff test.java, assuming you’ve put the .java files that were under /usr/share/stuff under /usr/share/stuff/org/name (or whatever is appropriate according to their package names).

Usually, Java developers face the “package does not exist” error when they import a package into their class. If you are one of them, it’s worth reading this article.

If you’re a Java developer, you may have encountered the “package does not exist” error at some point. This error occurs when the Java compiler is unable to find the package that you’re trying to use in your code.

In this article, we’ll discuss what is a package in Java and how to import a package in your java program to utilize the built-in functionalities. Furthermore, we’ll also discuss the most common error that Java developers face which is Java package does not exist. So without further ado, let’s dive deep into the topic.

What is a Package in Java?

A package is a collection of related interfaces and classes. It helps us to organize different classes and interfaces in a folder structure. Each package in Java must have a unique name; it stores different classes in a separate namespace. We have two types of packages:

1. Built-in Packages (Come with Java API)
2. User-defined Packages (User created packages)

Packages improve the reusability of code and make it easy to locate. Packages are mainly used to avoid name conflicts between classes. Although classes with the same name are not allowed to appear in a package, they may appear in different packages.

How to Create And Use a Java Package in Java?

To create a package, we have to choose a unique name for the package and write a package statement on the top of the source file. After that, we can define all the classes, interfaces, enumerations, and annotations types we want in our package. 

The general syntax of creating a package is as follows:

package packagename;

Let’s create a user-defined package but first see its folder structure:

We have two classes in the package(mypackage) and the Main class that contain the main function.

Code of class1 

package mypackage;


public class class1 {

   public void welcome(){

       System.out.println("Welcome to my Class1");

   }
}

Code of class2

package mypackage;


public class class2 {

   public void welcome(){

       System.out.println("Welcome to my Class2");

   }

}

Code of Main class in which we import our package and create objects of its classes.

// import all class of mypackage

import mypackage.*;

public class Main {

   public static void main(String[] args) {

       // creating object of class1 of mypackage

       class1 c1= new class1();

       c1.welcome();



       // creating object of class1 of mypackage

       class2 c2= new class2();

       c2.welcome();



   }

}

Output

Welcome to my Class1

Welcome to my Class2

We can also import just one class of package just we have to write import mypackage.class1; in place of import mypackage.*;

What is the “Package Does Not Exist” Error in Java?

As we understand what a package is and how it stores in computer memory, Now we can easily understand what package does not exist error and when it occurs. We are getting this error because the compiler can not find the package we mention.

As in the above example, if we write mypackage1 instead of mypackage then we will get this error:

Reasons and Solution for the Java “Package Does Not Exist” Error

Following are some of the main reasons this error occurs:

1. Write the wrong name of the package
2. Install packages properly
3. IDE Problem
4. Setting Class Path
5. The package does not exist

Now we’ll discuss these reasons one by one and see what the solution to these reasons:

Case 1: Writing The Wrong Name of The Package

Most of the time, we face this problem when we write the wrong package name. Always double-check the package’s name so you don’t face this problem again. As in the above example, if we write mypackage in place of mypackage1, the error will be gone.

If you’re typing the package name manually, it’s easy to make a typo. Make sure you’re spelling the package name correctly, and double-check that you’re using the correct capitalization.

Case 2: Install Packages Properly

Sometimes we face this problem when our required package is not installed properly. If you are using IntelliJ IDE, then the settings for installing a package are:

1. Click File menu
2. Select the Project Structure option
3. From the left pane, move to the Global libraries under the platform setting
4. Click the + symbol 
5. Select the required package from the hard disk you want to install

That being said, this issue can potentially occur if the package is not imported. To use a package in your Java code, you need to import it using the import keyword. If you forget to import the package, or if you import the wrong package, you’ll get the “package does not exist” error. Ensure you’re importing the correct package, and double-check that you’re using the correct import statement.

Case 3: IDE Problem

If you are using IntelliJ or Eclipse IDE and you installed the package or created the package but still facing the problem, in this case, you have to rebuild the project. In Eclipse, if you have a Java package does not exist error then follow these steps:

1. In the project folder, go to the src folder, cut all the files and folder from it to a temporary folder.
2. Build the project
3. Now copy all the files and folders from the temporary folder to the src folder.
4. Run the build again

Now you don’t have the package does not exist error again. 

Case 4: Setting Class Path

We face this problem when the Class Path of our package is not set. To use a package in Java, it must be on the classpath. The classpath is a list of directories and JAR files that the Java compiler searches for class files. If the package you’re trying to use is not on the classpath, you’ll get the “package does not exist” error. To fix this, you need to add the package to the classpath.

To do so, follow these steps.

1. Type Environment variables in the search box.
2. Select Edit Environment variable option from the search.
3. Select the Advanced tab.
4. Click on the Environment Variables button.
5. Click on the New button under System Variables.
6. Add CLASSPATH as the variable name and the package’s path as a variable value.
7. Select OK.

Case 5: The Package Does Not Exist

In rare cases, the “package does not exist” error might occur because the package you’re trying to use does not actually exist. This can happen if you’re trying to use a third-party library that has been removed or if you’re trying to use a package that has been deprecated.

Additional Fixes

Conclusion

By understanding the causes of the “package does not exist” error, you can more easily troubleshoot and fix the problem. Make sure the package is on the classpath, check the spelling and capitalization of the package name, import the package correctly, and verify that the package actually exists. With these tips, you should be able to fix the “package does not exist” error and get your Java code running smoothly.

Finally, at the end of this article, we conclude this topic with this statement that the Java package does not exist is commonly caused if you type the wrong name of the package or do not set the classpath. Still, we sometimes face this problem due to IDE; we must rebuild our project or install the package properly.

Let’s have a quick review of the topics discussed in this article.

1. What is a package?
2. How can we create and use a package?
3. What is the package does not exist error in Java?
4. Reasons and solutions for the Java package do not exist.

If you are satisfied with the information given in this article, don’t forget to share it with your coding mates, also comment below 👇 which solution has worked in your case.

Happy coding!🥳

1. Demonstration of Package Does Not Exist in Java
2. Resolve Package Does Not Exist Error in Java

Today, we will reproduce the package does not exist error in Java to understand the error and its reasons. Further, we will also learn about its solution with the help of code examples.

Demonstration of Package Does Not Exist in Java

Example Code (Students.java file):

package name;

public class Students implements Comparable<Students>{
    private String studentFirstName;
    private String studentLastName;

    public Students(String studentFirstName, String studentLastName){
        this.studentFirstName = studentFirstName;
        this.studentLastName = studentLastName;
    }

    public String getStudentFirstName() {
        return studentFirstName;
    }

    public void setStudentFirstName(String studentFirstName) {
        this.studentFirstName = studentFirstName;
    }

    public String getStudentLastName() {
        return studentLastName;
    }

    public void setStudentLastName(String studentLastName) {
        this.studentLastName = studentLastName;
    }

    /**
     *
     * @param other
     * @return
     */
    @Override
    public int compareTo(Students other) {

        int compareResults = this.studentLastName
                             .compareTo(other.studentLastName);

        if(compareResults == 0){
            if(this.studentFirstName.chars().count() ==
               other.studentFirstName.chars().count()) {
                compareResults = 0;
                return compareResults;
            }
            else if(this.studentFirstName.chars().count() >
                    other.studentFirstName.chars().count()){
               compareResults = 1;
               return compareResults;
            }
            else{
                compareResults =  -1;
                return compareResults;
            }
        }
        else{
            return compareResults;
        }
    }
}

Example Code (StudentMain.java file):

import names.Students;

public class StudentMain {

    public static void main(String[] args) {
        Students student1 = new Students ("Ali", "Ashfaq");
        Students student2 = new Students ("Ali", "Ashfaq");
        System.out.println("Comparison 1: " + student1.compareTo(student2));

        Students student3 = new Students ("Ali", "Ashfaq");
        Students student4 = new Students ("Zoya", "Ashfaq");
        System.out.println("Comparison 2: " + student3.compareTo(student4));

        Students student5 = new Students ("Mehr-un-nissa", "Ashfaq");
        Students student6 = new Students ("Hina", "Ashfaq");
        System.out.println("Comparison 3: " + student5.compareTo(student6));
    }
}

We have a directory Desktop/java/stuff/com/name where all our .java files are located except those containing the main() method. For the above code example, we have Students.java in the Desktop/java/stuff/com/name directory, while StudentMain.java with the main() method is in the Desktop/java/stuff/com directory.

It is also important to note that we have set Desktop/java/stuff to our CLASSPATH.

Let’s understand the code to figure out the error and its causes.

The above code compares the last names of the Students and stores the result in the compareResults variable. This result is further used to compare their first names. How?

If the last name matches, the result would be true means 0. So, it jumps to the if condition and assesses if the number of characters in their first names matches.

The result of comparing first names is based on the following conditions:

1. If this.count is equal to the other.count, the result will be 0.
2. If this.count is greater than the other.count, the result will be 1.
3. If this.count is less than the other.count, the result will be -1.

But, when we try to compile the program, it gives us the following error.

C:UsersMEHVISH ASHIQDesktopjavastuffcom>javac StudentMain.java
StudentMain.java:1: error: package names do not exist
import names.Students;

What does it mean, and why are we facing this problem? This error means the package we are trying to import does not exist.

There can be different reasons for that, and all of them are listed below:

1. We have imported the incorrect package, or we may have some typos while importing the package.

2. Recheck if all of the files are in the correct sub-directories.

3. If we have set our CLASSPATH to Desktop/java/stuff, then the files defined with package name; must reside in the Desktop/java/stuff/com/name directory. You may check this to learn how to set CLASSPATH.

4. Make sure all the Java source files are in the correct sub-directory. We must also ensure that the Java source files are compiled in the Desktop/java/stuff/com/name directory.

   Why? The .class files must be on the CLASSPATH. Remember, the .java files are not required to be on the CLASSPATH but SOURCEPATH, while .class files are generated when we compile the file using the javac command.

5. We also get this error if we don’t use the built-in package properly. See the following code:

Example Code:

public class Test{
    public static void main(String[] args){
        /*
        Solution: This line must be as follows:
        System.out.println("Hi!");
        */
        system.out.println("Hi!");
    }
}

Error Description:

Test.java:3: error: package system does not exist
                system.out.println("Hi!");
                      ^
1 error

Resolve Package Does Not Exist Error in Java

Example Code (Students.java file):

package name;

public class Students implements Comparable<Students>{
    private String studentFirstName;
    private String studentLastName;

    public Students(String studentFirstName, String studentLastName){
        this.studentFirstName = studentFirstName;
        this.studentLastName = studentLastName;
    }

    public String getStudentFirstName() {
        return studentFirstName;
    }

    public void setStudentFirstName(String studentFirstName) {
        this.studentFirstName = studentFirstName;
    }

    public String getStudentLastName() {
        return studentLastName;
    }

    public void setStudentLastName(String studentLastName) {
        this.studentLastName = studentLastName;
    }

    /**
     *
     * @param other
     * @return
     */
    @Override
    public int compareTo(Students other) {

        int compareResults = this.studentLastName
                             .compareTo(other.studentLastName);

        if(compareResults == 0){
            if(this.studentFirstName.chars().count() ==
               other.studentFirstName.chars().count()) {
                compareResults = 0;
                return compareResults;
            }
            else if(this.studentFirstName.chars().count() >
                    other.studentFirstName.chars().count()){
               compareResults = 1;
               return compareResults;
            }
            else{
                compareResults =  -1;
                return compareResults;
            }
        }
        else{
            return compareResults;
        }
    }
}

Example Code (StudentMain.java file):

import name.Students;

public class StudentMain {

    public static void main(String[] args) {
        Students student1 = new Students ("Ali", "Ashfaq");
        Students student2 = new Students ("Ali", "Ashfaq");
        System.out.println("Comparison 1: " + student1.compareTo(student2));

        Students student3 = new Students ("Ali", "Ashfaq");
        Students student4 = new Students ("Zoya", "Ashfaq");
        System.out.println("Comparison 2: " + student3.compareTo(student4));

        Students student5 = new Students ("Mehr-un-nissa", "Ashfaq");
        Students student6 = new Students ("Hina", "Ashfaq");
        System.out.println("Comparison 3: " + student5.compareTo(student6));
    }
}

We got the package does not exist error because of importing the wrong package in the StudentMain.java file. We were importing as import names.Students;, while it must be import name.Students;.

You may see all the commands below, including how we set the CLASSPATH.

Output:

C:UsersMEHVISH ASHIQ>cd Desktop/java/stuff
C:UsersMEHVISH ASHIQDesktopjavastuff>set classpath=.;
C:UsersMEHVISH ASHIQDesktopjavastuff>cd com/name
C:UsersMEHVISH ASHIQDesktopjavastuffcomname>javac Students.java
C:UsersMEHVISH ASHIQDesktopjavastuffcomname>cd..
C:UsersMEHVISH ASHIQDesktopjavastuffcom>javac StudentMain.java
C:UsersMEHVISH ASHIQDesktopjavastuffcom>java StudentMain
Comparison 1: 0
Comparison 2: -1
Comparison 3: 1

I’m afraid I’m able to reproduce. Here’s a diff I applied to enunciate-sample:

diff --git a/pom.xml b/pom.xml
index 332623b..ca961e8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -36,6 +36,7 @@
         <version>${enunciate.version}</version>
         <executions>
           <execution>
+            <phase>process-classes</phase>
             <goals>
               <goal>assemble</goal>
             </goals>
@@ -52,6 +53,13 @@
 
   <dependencies>
     <dependency>
+      <groupId>org.immutables</groupId>
+      <artifactId>value</artifactId>
+      <version>2.5.6</version>
+      <scope>provided</scope>
+    </dependency>
+
+    <dependency>
       <groupId>com.webcohesion.enunciate</groupId>
       <artifactId>enunciate-core-annotations</artifactId>
       <version>${enunciate.version}</version>
diff --git a/src/main/java/com/ifyouwannabecool/api/PersonaService.java b/src/main/java/com/ifyouwannabecool/api/PersonaService.java
index a1b238d..9b4f121 100644
--- a/src/main/java/com/ifyouwannabecool/api/PersonaService.java
+++ b/src/main/java/com/ifyouwannabecool/api/PersonaService.java
@@ -15,6 +15,7 @@ import javax.ws.rs.PathParam;
 import javax.ws.rs.Produces;
 
 import com.ifyouwannabecool.domain.persona.Persona;
+import com.ifyouwannabecool.domain.persona.Thing;
 
 /**
  * The persona services is used to perform actions on the data associated with a persona.
@@ -33,6 +34,10 @@ public interface PersonaService
     @GET
     Persona readPersona(@PathParam("id") String personaId);
 
+    @Path("/thing")
+    @GET
+    Thing getThing();
+
     @Path("/{id}.json")
     @GET
     @Produces("application/json")
diff --git a/src/main/java/com/ifyouwannabecool/domain/persona/Thing.java b/src/main/java/com/ifyouwannabecool/domain/persona/Thing.java
index 3aede1b..2256278 100644
--- a/src/main/java/com/ifyouwannabecool/domain/persona/Thing.java
+++ b/src/main/java/com/ifyouwannabecool/domain/persona/Thing.java
@@ -1,7 +1,14 @@
 package com.ifyouwannabecool.domain.persona;
 
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import org.immutables.value.Value;
+
 /**
  *
  */
+@Value.Immutable
+@JsonDeserialize(as = ImmutableThing.class)
 public interface Thing {
+
+  String getName();
 }
diff --git a/src/main/java/com/ifyouwannabecool/impl/PersonaServiceImpl.java b/src/main/java/com/ifyouwannabecool/impl/PersonaServiceImpl.java
index 72b8b7a..933edca 100644
--- a/src/main/java/com/ifyouwannabecool/impl/PersonaServiceImpl.java
+++ b/src/main/java/com/ifyouwannabecool/impl/PersonaServiceImpl.java
@@ -12,6 +12,7 @@ import javax.ws.rs.Path;
 import com.ifyouwannabecool.api.PermissionDeniedException;
 import com.ifyouwannabecool.api.PersonaService;
 import com.ifyouwannabecool.domain.persona.Persona;
+import com.ifyouwannabecool.domain.persona.Thing;
 
 /**
  * @author Ryan Heaton
@@ -28,6 +29,11 @@ public class PersonaServiceImpl implements PersonaService
         return persona;
     }
 
+    @Override
+    public Thing getThing() {
+        return null;
+    }
+
     public Persona readPersonaJson()
     {
         final Persona persona = new Persona();

I had no problem with setting the scope to provided; Enunciate picked up that artifact just fine.

I did have to change my Maven phase to process-classes in order to pick up the generated immutables classes, which are generated in the compile phase, which happens after the default Enunciate phase (process-sources).

Anyway, if you can send me an alternate diff that exposes the problem, I’d be happy to re-open and look into it further.