How to Add JARs to Project Build Paths in Eclipse (Java)

1. 1
   Copy the JARs you'll be using to your project. Here's how it's conventionally done:
   
   
   • Create a new folder named lib in your project folder. This stands for "libraries" and will contain all the JARs you'll be using for that project.
     
   • Copy the JARs you need to lib.
     
   • Refresh your project by right clicking the project name and selecting Refresh. The lib folder will now be visible in Eclipse with the JARs inside.
     
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2. 2
   Complete either of the following methods to finish configuring your build path.

Method 1

1. 
   1
   Expand lib in Eclipse and select all the JARs you need.
2. 
   2
   Right-click the JARs and navigate to Build Path.
3. 3
   Select Add to Build Path. The JARs will disappear from lib and reappear in Referenced Libraries.

Method 2

1. 
   1
   Right click the project name and navigate to Build Path.
2. 
   2
   Select Configure Build Path... and the project properties window will appear showing your build path configurations.
3. 
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   Select the Libraries tab.
4. 
   4
   Click Add JARs...
5. 
   5
   Locate and select the JARs you want and click OK. The JARs will now appear in the list of libraries in the build path.
6. 
   6
   Click OK to close the properties window. The JARs will now be in Referenced Libraries instead of lib.

Note: It is much better to reference JARs that exist in your project or in other projects - this allows you to check in all of your dependencies to your version control system. (You are using version control, right?)

Use one of the following methods.

Method 1

This is the preferred method, as it allows different developers of a common project to locate their external jars in different places.

1. 
   1
   Right click the project name and navigate to Build Path.
2. 
   2
   Select Configure Build Path... and the project properties window will appear showing your build path configurations.
3. 
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   Click Add Variable...
4. 
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   Click Configure Variables...
5. 
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   Click New...
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   Type a name for the new variable. For example, if these are JARs for Tomcat, perhaps call it TOMCAT_JARS
7. 
   7
   Browse to the directory that contains the JAR for the path. (You can also select a specific jar file for the variable, if you prefer.)
8. 
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   Click Ok to define the variable.
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   Click Ok to close the preferences dialog.
10. 
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    Select the variable from the list.
11. 
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    Click Extend...
12. 
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    Select the JAR(s) that you want to add to the classpath.
13. 
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    Click Ok to close the extend dialog.
14. 
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    Click Ok to close the new classpath variable dialog.
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    15
    Click Ok to close the build path setup dialog.
    • If you share the project with someone else, they must also define the variable. They can define it under
      
      Window->Preferences->Java->Build Path->Classpath Variables
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Method 2

Note that if you use this method, the external JAR will need to be in the same location on the hard drive for anyone who uses this project. This can make sharing a common project more difficult.

1. 
   1
   Right click the project name and navigate to Build Path.
2. 
   2
   Select Add External Archives...
   
   
3. 
   3
   Locate and select the JARs you want and click Open. The JARs will now appear in Referenced Libraries.
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Method 3

Note that if you use this method, the external jar will need to be in the same location on the hard drive for anyone who uses this project. This can make sharing a common project more difficult.

1. 
   1
   Right-click the project name and navigate to Build Path.
2. 
   2
   Select Configure Build Path... and the project properties window will appear showing your build path configurations.
3. 
   3
   Select the Libraries tab.
4. 
   4
   Click Add External JARs...
5. 
   5
   Locate and select the JARs you want and click Open. The JARs will now appear in the list of libraries in the build path.
6. 
   6
   Click OK to close the properties window. The JARs will now be in Referenced Libraries.
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