LDAP Connection: FAILED

javax.naming.NoInitialContextException: Cannot instantiate class: com.sun.jndi.ldap.LdapCtxFactory; [Root exception is java.lang.ClassNotFoundException: com/sun/jndi/ldap/LdapCtxFactory;]

I am trying to connect to ldap using

LDAP Query: Retrieve Basic User Attributes in Java | DeepakGaikwad.net

I am getting this error.How to resolve.