Description of problem:
Some designer unit tests failing when run with Java 8

Version-Release number of selected component (if applicable):
bpms 6.2.0GA

Steps to Reproduce:
1. Set up Java 8 on your machine
2. In jbpm-designer/jbpm-designer-backend run "mvn clean test"
3. In jbpm-designer/jbpm-designer-client run "mvn clean test"

Actual results:
These unit tests have test failures:
org.jbpm.designer.repository.servlet.AssetServiceServletTest.testListAssets
org.jbpm.designer.repository.servlet.AssetServiceServletTest.testGetAssetInfoByPath
org.jbpm.designer.repository.servlet.AssetServiceServletTest.testGetAssetInfoById
org.jbpm.designer.client.shared.AssignmentTest.initializationError

Expected results:
All unit tests should pass

Additional info: