java.lang.NoClassDefFoundError: sun/io/CharacterEncoding JDK Error Oracle SOA

While using JDK 8, following error might come in Oracle SOA.

java.lang.NoClassDefFoundError: sun/io/CharacterEncoding
at oracle.j2ee.ws.common.util.TestPageUtils.encode(TestPageUtils.java:216)
at oracle.j2ee.ws.server.management.mbeans.WebServiceOperation.createTestPagePath(WebServiceOperation.java:276)

Look like its not supported version of JDK for SOA. Try to install JDK 7 and then test. This error must resolve.