class not found add jar via eclipse - java

When I was working with java spring hibernate struts2 eclipse project. I used buildpath-> addjar option to add jars from a folder inside the workspace. Even if the class is available it shows class not found exception.
If i put those jar files in web-inf/lib folder everything works.. Should i keep those files in the lib itself? Can i just include those jars in a seperate folder and add jar using eclipse configure build path??
what is the problem ? please help me... thanks in advance...

If you're using a standard Eclipse Dynamic web project, best way to go is to put all your Jars in the WEB-INF\lib folder. This will automatically add them to your build path and also include them in your WAR when you export it.
If you still want to use the Build Path > Add Jar option on the project, and want your Jars to also be included in your WAR, you have to go to the Project Properties > Deployment Assembly configuration and include them there. Of course this is double the work for every Jar.

Related

How Can i add Library Jar files into the modules

I am trying to use loaded jar files of my class path into my module. I
know requires will accept only modules names.
my jar files are present inside the Spring Jar Files folder.
I tried to use #Configuration annotation inside my appConfig.java file and IDE could not recognize it.
Your help is much appreciated as I am new to the programming world.
Normally, I use Maven or Gradle to handle all the jars.
It seems you have just started with Spring.
I suggest you try Spring Boot with Maven or Gradle to manage the library and the code lifecycle (compile, build, test).
This is one tutorial for example: https://spring.io/guides/gs/spring-boot/
You can add a jar in Eclipse by right-clicking on the Project → Build Path → Configure Build Path. Under Libraries tab, click Add Jars or Add External JARs and give the Jar.
Example link
The above solution is obviously a "Quick" one. However, if you are working on a project where you need to commit files to the source control repository, I would recommend adding Jar files to a dedicated library folder within your source control repository and referencing few or all of them as mentioned above.
I'd suggest go for the second one if you are planning to build this as a proper project and put it in a source control repo.

how to package the .class under the web-inf/classes as a jar and put it to the web-inf/lib dir

I have a java web application name webapp,when I export it to a war,the source codes will be compiled to the WEB-INF/classes.
Now I want these classed be compressed to a jar,and put into the WEB-INF/lib.
I have tried this:
create a new java project named webapp_jar.
Copy all the source codes under the webapp/src to the webapp_jar/src,configurate the build path to make the project work.
Add the webapp_jar reference to webapp project.
However ,when I run the webapp,it seems that the classes defined at webapp_jar can not be found.
Is this possible?
BTW,I use the eclipse ee ide.
have you try ant https://ant.apache.org/ ?
you could make a jar and copy it to folder you want and build the war after.
But , if I anderstand, you would package all the app to a jar ?
I think your webapp can't work without a servlet or two ...
This is really easy to do with maven by creating two subject projects, one to build the war, and the other as a jar project and then use the jar project as a dependency on your war project which would put the jar inside the lib directory when packaging the war.
No I use the Web Deployment Assembly settings in eclipse. I worked.
You can find details here.

Getting NoClassDefFoundError when using common.lang.StringUtils in android java code?

I am getting this error:-NoClassDefFoundError wherever the code is using StringUtils class or methods .I have correctly added the jar files to the code and is not showing any kind of error in my code(Using Eclipse Indigo).
Is there any kind of point I am missing out. I have used this jar file in other projects but they worked properly.
Please help If any one is getting similar kind of problem?Thanks
Yes, this because of your .jar file didn't import properly. Follow below steps -
Place your .jar file in your project's libs folder .
Import it into your project. And, GoTo project -> properties -> Java build path -> order tab.
Check, whether your .jar file checked and placed in order of 1st. This is the main thing.
Hope these steps helps you. Have a look at below image -
Note that the build classpath is different from the runtime classpath. You must add the required JARs to both.
It's one of the things I don't like in Eclipse...
EDIT: To add JARs to the runtime classpath: in Eclipse, double click the plugin.xml file associated with your project. On the Runtime tab there is a Classpath category. From there, you can add JARs to the runtime classpath.
Here is a screenshot to illustrate this:
Are the jar files in a lib folder or a libs folder?
Newer SDKs require the jar files to be in a libs folder.
I do not know how you execute your code, but it clearly means that the jar is not properly added to your classpath, especially if your code compiles in Eclipse.
Add it to your classpath -or re-check it is well added- when executing and it should work.
Right click on project, Select Build Path -> Configure Build Path and Select Libraries tab. Then with add Jars, add the jar in question.(if you are using eclipse)

Adding Jar File to WEB-INF/lib

I new in Eclipse,Java and Linux. I search about this issue but I don't reach to answer. I want to write a program that manipulate HBase Tables. So I have some Jar files that they related to the HBase. In ordinary Java application I add Jar files through following instruction
Build Path -> Configuration Build Path -> Add External Jars
So in Dynamic Web Project sound like different. after some search I understand the Jar files must be added in WEB-INF/lib or in %TOMCAT_HOME%/lib. so I get answer from %TOMCAT_HOME%/lib but really stuck about how to add jar files in WEB-INF/lib. I copy all jar files in the folders but it doesn't work.
please help me in detail.
you are doing right....
Build Path -> Configuration Build Path -> Add External Jars
In "Order and Export" tab click on select all...
or coping file into WEB-INF/lib
Then just refresh your project and restart the server then deploy the project it will work fine...
as Cultor said its right process but you must be refresh project after adding jar files.
Build Path -> Configuration Build Path -> Add External Jars
To add jars in eclipse you have two options:
Right click on project got to properties-->click on java build path --> configure build path--> Libraries --> and select add external jars button.
It will open a window where you can add all your jars required.
Second option is to paste jars directly to lib folder.
lib folder is in Web Content --> WEB-INF --> lib.
Use any one of them.
You can copy jar files manually to WEB-INF/lib when you have your project open in eclipse, then while modifying build path, just click "add jars" button and refer a jar from WEB-INF/lib . By this when you deploy your project to tomcat, your WEB-INF/lib folder gets copied automatically.
You can drag the MySQL jar file from external folder where it is located in your computer into the lib of your project..
If a path to the jar file is too long it will not paste that jar file.
Paste the jar file on the desktop and try again.
This works for me.

How can I add JAR files to the web-inf/lib folder in Eclipse?

I'm using Eclipse and I need to be able to add Java libraries (JAR files) into my web application's WEB-INF/lib folder. How do I achieve this?
Add the jar file to your WEB-INF/lib folder.
Right-click your project in Eclipse, and go to "Build Path > Configure Build Path"
Add the "Web App Libraries" library
This will ensure all WEB-INF/lib jars are included on the classpath.
Found a solution.
This problem happens, when you import a project.
The solution is simple
Right click -> Properties
Project Facets -> Check Dyanmic Web Module and Java Version
Apply Setting.
Now you should see the web app libraries showing your jars added.
Pasting the jar files in WebContent\WEB-INF\lib via the file system was the only way it worked for me.
They then appeared under the Deployed Resources and WebContent lib sub-folders.
When I looked, the build path had the jars in the Web App Libraries and everything built and ran fine.
They are automatically added to the project classpath if its a web project. Sometimes it does not work properly, a refresh or close/open of the project helps.
if its not a web project you can right click on the library and go to "Build Path" -> "Add to Build Path"
add the jar to WEB-INF/lib from file structure
refresh the project, you should see the jar now visible under the WEB-INF/lib folder.
add the jar to WEB-INF/lib from file structure
refresh the project, you should see the jar now visible under the WEB-INF/lib folder.
this is the best solution that worked for me
Check under project properties -> deployment assembly
if jar file are under deployed path- WEB-INF/lib
if not use add button and add jar under WEB-INF/lib
sometime eclipse (in my case Juno Service Release 2 ) was not doing it for me so i did manually. this worked for me.
From the ToolBar to go
Project> Properties>Java Build Path > Add External Jars.
Locate the File on the local disk or web Directory and Click Open.
This will automatically add the required Jar files to the Library.
In case this helps anyone, if you are using a Git repo, make sure the jars make it into the WEB-INF/lib INSIDE the git repo and not just in the project WEB-INF/lib
Add the jar file to your WEB-INF/lib folder.
Right-click your project in Eclipse, and go to "Build Path > Configure Build Path"
Add the "Web App Libraries" library
This will ensure all WEB-INF/lib jars are included on the classpath.
helped me..
Drag and drop in WEB-INF/lib folder and restart eclipse ans start webservice then create client

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