https://tomcat.apache.org/: JSP package 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package jakarta.servlet.jsp.el;



This class is used to customize the way an ExpressionEvaluator resolves
variable references at evaluation time. For example, instances of this class
can implement their own variable lookup mechanisms, or introduce the notion
of "implicit variables" which override any other variables. An instance of
this class should be passed when evaluating an expression.




An instance of this class includes the context against which resolution will
happen



Since:2.0
Deprecated:As of JSP 2.1, replaced by jakarta.el.ELResolver
/**
 * <p>
 * This class is used to customize the way an ExpressionEvaluator resolves
 * variable references at evaluation time. For example, instances of this class
 * can implement their own variable lookup mechanisms, or introduce the notion
 * of "implicit variables" which override any other variables. An instance of
 * this class should be passed when evaluating an expression.
 * </p>
 * <p>
 * An instance of this class includes the context against which resolution will
 * happen
 * </p>
 *
 * @since 2.0
 * @deprecated As of JSP 2.1, replaced by jakarta.el.ELResolver
 */
@Deprecated
public interface VariableResolver {

    
Resolves the specified variable. Returns null if the variable is not
found.

Params:
  • pName – 
           the name of the variable to resolve
Throws:
  • ELException – 
            if a failure occurred while trying to resolve the given
            variable
Returns:the result of the variable resolution
/**
     * Resolves the specified variable. Returns null if the variable is not
     * found.
     *
     * @param pName
     *            the name of the variable to resolve
     * @return the result of the variable resolution
     * @throws ELException
     *             if a failure occurred while trying to resolve the given
     *             variable
     */
    public Object resolveVariable(String pName) throws ELException;
}