http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.7. 
package org.bouncycastle.asn1.x9;

public abstract class X9ECParametersHolder
{
    private X9ECParameters params;

    public X9ECParameters getParameters()
    {
        if (params == null)
        {
            params = createParameters();
        }

        return params;
    }

    protected abstract X9ECParameters createParameters();
}