If JCE is already installed, you should see on that the jar files ‘local_policy.jar’ and ‘US_export_policy.jar’ are on $JAVA_HOME/jre/lib/security/

But, we can test it:

import javax.crypto.Cipher;
import java.security.*;
import javax.crypto.*;

class TestJCE {
 public static void main(String[] args) {
 boolean JCESupported = false;
 try {
    KeyGenerator kgen = KeyGenerator.getInstance("AES", "SunJCE");
    kgen.init(256);
    JCESupported = true;
 } catch (NoSuchAlgorithmException e) {
    JCESupported = false;
 } catch (NoSuchProviderException e) {
    JCESupported = false;
 }
    System.out.println("JCE Supported=" + JCESupported);
 }
} 

To compile (assuming file name is TestJCE.java):

$ javac TestJCE.java

Previous command will create TestJCE.class output file.

To Interpreting and Running the program:

$ java TestJCE