If statement inconsistency?

Question

Yay! Another post from me!
I've got an if statement in a bean that seems to be processing fine when I create a test java class, but doesn't work fine when the bean is invoked by a jsp.
My code, let me shows you it:
First, the test class:
package com.serco.inquire;
import java.util.*;
import java.text.*;
public class TestCollection {
     public static void main(String[] args) {
          IrCollection myCollection = new IrCollection();
          myCollection.setSort("none");
          myCollection.setMgrid("none");
          int endpoint = myCollection.getSize();
          for (int i=0;i<endpoint;i++) {
               InquireRecord curRec = myCollection.getCurRecords(i);
               Long milis = new Long(curRec.getSubmitDate());
               Date theDate = new Date(milis);
               Format formatter = new SimpleDateFormat("dd MMM yyyy");
               String s = formatter.format(theDate);
               System.out.println("ID: " + curRec.getID() + " | Subject: " + curRec.getSubject());
}a snippit from the IrCollection class it calls:
private void processSort(String datum) {
          int LastChar = datum.length()-1;
          String colName = datum.substring(0, LastChar);
          if (datum=="none") {
               this.fullSort  = " ORDER BY lastUpdated DESC";
          } else {
               if (datum.endsWith("2")) {
                    this.fullSort = " ORDER BY " + colName + " ASC";
               } else {
                    this.fullSort = " ORDER BY " + colName + " DESC";
     }There's more code in another method that calls this particular method using: this.processSort(this.sort);But the problem is that if (datum=="none") portion in the second code sample. Given that line 10 of the first class sets the member variable sort to "none", that processSort() method should set the member variable fullSort to " ORDER BY lastUpdated DESC"
And if I use the class in the first sample, it does that.
HOWEVER
I have this custom tag:
<%@ tag body-content="scriptless" import="com.serco.inquire.*" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ attribute name="mgr" required="true" %>
<%@ attribute name="mkind" required="false" %>
<%@ attribute name="sort" required="false" %>
<c:if test="${empty mkind}">
  <c:set var="mkind" value="manager" />
</c:if>
<c:if test="${empty sort}">
  <c:set var="sort" value="none" />
</c:if>
<jsp:useBean id="irc" scope="page" class="com.serco.inquire.IrCollection">
  <jsp:setProperty name="irc" property="mgrtype" value="${mkind}" />
  <jsp:setProperty name="irc" property="sort" value="${sort}" />
  <jsp:setProperty name="irc" property="mgrid" value="${mgr}" />
</jsp:useBean>
${irc.fullsort}Which the .jsp file invokes with this:
<c:set var="user" value="none" />   
<c:set var="sort" value="none" />
<inq:displayCollection>
  <jsp:attribute name="mgr">${user}</jsp:attribute>
  <jsp:attribute name="mkind">cotr</jsp:attribute>
  <jsp:attribute name="sort">${sort}</jsp:attribute>
</inq:displayCollection>In other words, the exact same data is fed to the IrCollection bean. so I should get the same data, right?
Except I get this: WHERE cotr = 'none' ORDER BY non DESC so when Java calls it, it thinks "none" == "none"
but when jsp calls it, it thinks "none" != "none"

Answer 1

To compare objects' states, including Strings' contents, use equals(), not ==. The == operator tests whether 2 references have the same value, that is, whether both point to the same object (or are both null). The equals() method does whatever that class's implementor tells it to do, but its purpose--and what it does in reasonable implementations--is to compare objects' states. In the case of String, it tests whether both String objects contain equal character sequences.
If == happened to return true in your test case, its because interning led to both references pointing to the same String object in the constant pool.