Checking the specified class contains a field matching the specified name using Java Reflections

Overview

In this tutorial we check if the specified field exists for a class. We make use of Java Reflections.

Lets Begin

Initially using Java Reflections the class fields are looped and stored in a HashSet. Then later if it is to be checked if a field exists for the class it is checked if it is present in the properties Set created before. Create the Employee class as follows-

package com.javainuse.domain;

    public class Institute {
    
    private String name;
    private int code;
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getCode() {
        return code;
    }
    public void setCode(int code) {
        this.code = code;
    }
}
    

package com.javainuse.main;

import java.lang.reflect.Field;
import java.util.HashSet;
import java.util.Set;
import com.javainuse.domain.Institute;

public class CheckFieldMain {

    public static void main(String[] args) {
        Institute institute = new Institute();
        Set<String> sourceFieldList = getAllFields(institute.getClass());
        boolean hasName = ifPropertpresent(sourceFieldList, "name");
        System.out.println(hasName);
        boolean hasAddress = ifPropertpresent(sourceFieldList, "address");
        System.out.println(hasAddress);
    }
    
/**
 * Check if field is present for the class
 * @param properties
 * @param propertyName
 * @return
 */
    private static boolean ifPropertpresent(final Set<String> properties, final String propertyName) {
        if (properties.contains(propertyName)) {
            return true;
        }
        return false;
    }

    /**
     * Recursive method to get fields
     * 
     * @param type
     * @return
     */
    private static Set<String> getAllFields(final Class<?> type) {
        Set<String> fields = new HashSet<String>();
        //loop the fields using Java Reflections
        for (Field field : type.getDeclaredFields()) {
            fields.add(field.getName());
        }
        
        //recursive call to getAllFields
        if (type.getSuperclass() != null) {
            fields.addAll(getAllFields(type.getSuperclass()));
        }
        return fields;
    }
}
    

Download Source Code

Download it - Java project to check if field is present in class

See Also

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Java - PermGen space vs MetaSpace 
Java 8 Lambda Expression- Hello World Example 
Java 8 Features
Java Miscelleneous Topics
Java Basic Topics
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