// Then
        assertEquals(appendedReferral, initialReferral.next,
                "The 'next' property of the initial referral should point to the appended referral.");
        assertEquals(initialReferral, appendedReferral.next,
                "The 'next' property of the appended referral should point back to the initial referral, closing the loop.");
    }

    /**
     * Tests the toString method of the DfsReferral class.

     * If the property is not already set, it will be initialized with this package.
     * If the property is set but does not contain this package, the package will be appended.
     */
    default void initialize() {
        final StringBuilder buf = new StringBuilder(100);
        final String value = System.getProperty("java.protocol.handler.pkgs");
        if (StringUtil.isEmpty(value)) {

    /**
     * Appends a filter to an existing filter chain.
     *
     * @param filter the filter to append
     * @param chain the existing filter chain to append to
     * @return a new filter chain that includes the appended filter
     */
    protected FilterChain appendFilterChain(final Filter filter, final FilterChain chain) {
        return (context, query, boost) -> filter.execute(context, query, boost, chain);
    }

    /**

log4j.rootLogger=INFO,STDOUT
log4j.appender.STDOUT=org.apache.log4j.ConsoleAppender
log4j.appender.STDOUT.ImmediateFlush=true
log4j.appender.STDOUT.layout=org.apache.log4j.PatternLayout

log4j.rootLogger=WARN,STDOUT
log4j.appender.STDOUT=org.apache.log4j.ConsoleAppender
log4j.appender.STDOUT.ImmediateFlush=true
log4j.appender.STDOUT.layout=org.apache.log4j.PatternLayout
log4j.appender.STDOUT.layout.ConversionPattern=%-5p %d [%t] %m%n

log4j.rootLogger=INFO,STDOUT
log4j.appender.STDOUT=org.apache.log4j.ConsoleAppender
log4j.appender.STDOUT.ImmediateFlush=true
log4j.appender.STDOUT.layout=org.apache.log4j.PatternLayout

package org.codelibs.fess.util;

import java.util.Arrays;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.appender.rewrite.RewritePolicy;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;