package com.paritytrading.philadelphia;

/**
 * The protocol version.
 */
public enum FIXVersion {
    FIX_4_2("FIX.4.2"),
    FIX_4_3("FIX.4.3"),
    FIX_4_4("FIX.4.4"),
    FIXT_1_1("FIXT.1.1");

    private String beginString;

    private FIXVersion(String beginString) {
        this.beginString = beginString;
    }

    /**
     * Get the BeginString(8).
     *
     * @return the BeginString(8)
     */
    public String getBeginString() {
        return beginString;
    }

}

@@ -203,16 +203,22 @@
 private 
+final 
 String b

Use 'final' modifier in 'FIXVersion'