You may use the jdk1.5 package, while the development is used by the jdk1.6, do not allow 1.5 to install
Method 1, select the project Properties, choose Project Facets, right-click Select Java, Change Version ... Can
Law 2, in the project directory there is a. Settings folder, under which there is a org.eclipse.wst.common.project.facet.core.xml file with the following contents;
Modify <installed facet= "java" version= "1.6"/> to <installed facet= "java" version= "1.5"/>.
<?xml version= "1.0" encoding= "UTF-8"?><faceted-project> <fixed facet= "Jst.java"/> < Fixed facet= "Jst.web"/> <fixed facet= "Wst.jsdt.web"/> <installed facet= "java" version= "1.5"/ > <installed facet= "Jst.web" version= "2.5"/> <installed facet= "Wst.jsdt.web" version= "1.0"/ > <installed facet= "Jst.java" version= "5.0"/></faceted-project>
Project Facet Java version 1.6 is not supported