How to find node by name in Binary Search Tree in Java
<hr>

<p>I write method to find node of student records by the first and last name of student in Binary Search Tree</p>

<p>This is the code of the method in class Binary Search Tree</p>

<pre><code>private Student root;

public Student findNodeName(String firstname,String lastname) {

    return findNodeName(root,firstname,lastname);

}

private Student findNodeName(Student student,String firstname,String 
 lastname){


    if (student == null) {
        return null;
    }


    else if (firstname.equals(student.getFirstName())
            &amp;&amp;lastname.equals(student.getLastName())) {   
        return student;
    }

    else
    {
        if(student.getLeft()!= null)  
        return findNodeName(student.getLeft(),firstname,lastname);

    else 
        return findNodeName(student.getRight(),firstname,lastname);
    }

}
</code></pre>

<hr>

<p>And This code in main class</p>

<pre><code>//declare object of class universitydbmsBST
 universitydbmsBST universitydbmsbst;

if (command.equals("SEARCHNAME") == true) {

        //variables to read from input file
        String firstname = input.next();
        String lastname = input.next();

        //variable used to check if the student is already in BSt or not 
        Student student =null;


       //print if the student found or not
        if((student = 
             universitydbmsbst.findNodeName(firstname,lastname))!=null){

            output.println("SEARCHNAME Command");
            output.println("Found:  ID "+student.getID()+",  
            "+student.getFirstName()+" "+student.getLastName());

        }


        else {

            output.println("SEARCHNAME Command");
             output.println(student.getFirstName()+" 
             "+student.getLastName()+" was not found in 
              FCITbook.");

        }

    }
</code></pre>

<hr>

<p>But I have a problem when I do run it appears NullPointerException</p>

<p>Can anyone help me?</p>