Access restriction: Is not accessible due to restriction on required library ..\jre\lib\rt.jar

I ran into something similar, I think that the cause of the warning is Eclipse trying to discourage you from using the internal com.sun packages that are installed as part of your workspace JRE but which are not part of the public Java API.

As Justin says in his answer, changing your compiler settings can hide the warning. A more fine-grained approach is to modify your build path to explicitly allow access to the package in question:

1. Open the Libraries tab of the Java Build Path project property window.
2. Expand the JRE System Library entry.
3. Select "Access rules" and hit the Edit button.
4. Click the Add button in the resulting dialog.
5. For the new access rule, set the resolution to Accessible and the pattern to "com/sun/xml/internal/**".

After adding this access rule, your project should build without these warning.

Excellent answer already provide onsite here.

See the summary below:

1. Go to the Build Path settings in the project properties.
2. Remove the JRE System Library
3. Add it back; Select "Add Library" and select the JRE System Library. The default worked for me.

Not a true solution, but everywhere I looked the solution suggested was to simply tell Eclipse that those aren't errors. You can change it by going to Properties --> Java Compiler --> Errors Warnings --> Deprecated and restrited APIs --> Forbidden reference (acess rule), Change it from Error to Warning or Ignore.

i've solved this issue with these steps: expand your project, right click "JRE System Library" > Properties > choose 3rd option "Workspace default JRE" > OK . Hope it help you too

In Eclipse:
Project -> properties -> java Build Path -> libraries

Remove existing JRE System Library, then Add Library -> JRE System library -> next -> ok

Error will be removed.