We have the following plug-ins with minimum execution environments - J2SE-1.5:
org.jboss.ide.eclipse.archives.core
org.jboss.ide.eclipse.archives.jdt.integration
org.jboss.ide.eclipse.archives.test
org.jboss.ide.eclipse.archives.ui.test
org.jboss.ide.eclipse.archives.ui
org.jboss.ide.eclipse.archives.webtools
org.jboss.ide.eclipse.as.classpath.core
org.jboss.ide.eclipse.as.classpath.ui
org.jboss.ide.eclipse.as.doc.user
org.jboss.ide.eclipse.as.test
org.jboss.ide.eclipse.as.wtp.core
org.jboss.ide.eclipse.as.wtp.ui
org.jboss.tools.archives.scanner
org.jboss.tools.birt.oda.ui
org.jboss.tools.birt.oda
org.jboss.tools.esb.core
org.jboss.tools.esb.project.core
org.jboss.tools.esb.project.ui
org.jboss.tools.esb.ui
org.jboss.tools.foundation.security.linux
org.jboss.tools.jmx.core.test
org.jboss.tools.jmx.core
org.jboss.tools.jmx.ui.test
org.jboss.tools.jmx.ui
org.jboss.tools.jsf.doc.user
org.jboss.tools.maven.apt.parent/org.jboss.tools.maven.apt.core
org.jboss.tools.maven.apt.parent/org.jboss.tools.maven.apt.ui
org.jboss.tools.portlet.core
org.jboss.tools.portlet.ui
org.jboss.tools.seam.doc.user
org.jboss.tools.usage
org.jboss.tools.ws.core
org.jboss.tools.ws.creation.core

Probably, we should change it to JavaSE-1.6