Category: Professional


I have an uncontrollable urge to refactor. To a fault. Most everything. If I was cleaning a campsite, I would be putting in indoor plumbing. So, when I opened an old class I changed the old hashcode and equals methods with our team’s standard use of HashBuilder and EqualsBuilder. (The reason for opening the class was to add a toString method.)

@Override
public boolean equals(Object obj) {
    if (this == obj) {
        return true;
    }
    if (obj == null) {
        return false;
    }
    if (!(obj instanceof ${enclosing_type})) {
        return false;
    }
    ${enclosing_type} other = (${enclosing_type}) obj;
    ${builderType:newType(org.apache.commons.lang3.builder.EqualsBuilder)} ${builder:newName(builderType)} = new ${builderType}();
    ${builder}.append(this.${field}, other.${field}());${cursor}

    return ${builder}.isEquals();
}

When I ran the application again (I was trying to find a bug) I wasn’t getting to the same place in the code as before. Stepping through with the debugger I noticed that I was no longer returning “true” during a comparison of the object I had just changed. So I went back to the old version of the equals method. I could not visually see a difference. So I wrote a JUnit test case to test the equals method, specifically for symmetry. That didn’t get me very far; everything passed as expected.

So I ran the program through the debugger stopping in the equals method for comparison. It looked like the passed in object had nulls for everything. I changed my JUnit tests to test for the same setup, but it worked as expected.

So I went back and created 2 equals methods. Then I had each run and if there was a difference between the old equals method and the new equals method, I would just exit the program:

@Override
public boolean equals(final Object obj) {
    // TEMPORARY!!! 
    final boolean newEquals = newEquals(obj);
    final boolean oldEquals = oldEquals(obj);
    if (newEquals != oldEquals) {
        newEquals(obj); // for debugging, I can step through the method again 
        oldEquals(obj); // for debugging, I can step through the method again
        LOGGER.error("newEquals (" + newEquals + ") doesn't equal oldEquals (" + oldEquals + ")!!!");
        LOGGER.error("this = " + this);
        LOGGER.error("obj = " + obj);
        System.exit(1); // TEMPORARY!!!
    } 
    return oldEquals;
}

I re-ran the JUnit test, but still no luck.

I re-ran the application and viola the equals methods were different and the app exited. But what was going on?

I added a breakpoint in the equals method and looked at the state of the variables again. That’s when I noticed the my object being passed in wasn’t what I expected, but some kind of proxy object. I expanded the object and found a target variable. I expanded that and saw the values matched the “this” object!

Equals Comparison Screenshot

I looked back at the equals methods. The original equals method has get() and mine had just the direct access to the member variable. I step throw the call to the get method and found the proxy will load the member variables to their real values.

So, the lesson I learned was that I need to be calling the get methods in my equals method for the object being passed in. I changed my equals template to add a long-winded explanation for the change. Here’s my Eclipse template:

@Override
public boolean equals(Object obj) {
    if (this == obj) {
        return true;
    }
    if (obj == null) {
        return false;
    }
    if (!(obj instanceof ${enclosing_type})) {
        return false;
    }
    ${enclosing_type} other = (${enclosing_type}) obj;
    ${builderType:newType(org.apache.commons.lang3.builder.EqualsBuilder)} ${builder:newName(builderType)} = new ${builderType}();
    // You want to use get() methods because ${enclosing_type} might by a "proxy" that libraries (such as Hibernate with CGLIB) will create. (Hibernate uses proxies for lazy loading.) And if the object is not loaded, then access to the fields directly will yield nulls. But calls to the get() methods are intercepted and the proxy returns the correct value. See https://forum.hibernate.org/viewtopic.php?t=946468
    ${builder}.append(this.${name}, other.get${name}());${cursor}

    return ${builder}.isEquals();
}

Thanks go to this post for helping me understand the issue.

I guess this was already known by some, but I didn’t know that if you sublist a List that was Serializable, you will get back a list that is not.


import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

public class SerializableSubListTest {
   public static void main(String[] args) {
     List list = new ArrayList();
     list.add(new Serializable(){private static final long serialVersionUID = 1L;});

     System.out.println("list instanceof Serializable = " + (list instanceof Serializable));

     List subList = list.subList(0, 1);

System.out.println("subList instanceof Serializable = " + (subList instanceof Serializable));
   }
}

list instanceof Serializable = true
subList instanceof Serializable = false

Slash
Biltboard.com will be launching a new app to capture your work in progress process.

Momomaha.com
You have to develop a thick skin to blog about your personal life. And not everyone will like you — accept it.

5 things you can do to motivate your team:

  1. Stand up
  2. Hurry up
  3. Shut up
  4. Pair up – not just programming
  5. Think up – think positively

How To Work with Your Spouse
Communicate! But don’t talk about work at home or home at work.
Having a 3rd person to settle debates is good.

Manage Users like a Roman Centenarian
Accept what is not in your control. Prepare for the worst.

They could charge double the price and it would still be a great deal!

There is a PMD rule that checks for mutators (getters and setters) on Java Beans: BeanMembersShouldSerialize. I have a lot of these violations in my code. I’d rather understand the issue than just turn it off, but I’m struggling with what it means.

What I learned is: being Serializable does not make a class a Java Bean. And, to be Serializeable, you don’t need mutators.

But PMD thinks my object is a bean. Why? View full article »

I have an idea for an online list making app. The list can be sorted on any number of attributes (or “sorts”). Attributes can be added at any time and once “activated” you can drag and drop your list to the order you want for that attribute. Then, if you go to another attribute, it again can be drag and dropped into order, but the order is remembered. So if you go back to the first attribute, the items are resorted based on that attribute.

View full article »

I recently read the article Tech Lead Checklist to Kick your Team into Gear, recommended by my tech lead. Here are some things our team does and does not do.

Daily

Require written standup reports each day Nope. We don’t do this. Once every other week I might write something up but it contains more than what I did that day. And other times when someone (one person in particular) can’t attend our scrum they will send an email.
Attend a daily chat Yup. That’s our daily scrum.
Resolve roadblocks Yes, I do this.
Look at individual detailed activity Really? I peruse Fisheye occasionally, but I don’t think I do any “detailed” investigation.
Move requests to ticket system Yea, I usually put in “issues” which can be turned into backlogs during sprint planning.
Let team members select their own tasks. We try to let our developers do that. But some ask what they should work on and I do assign tasks.
Watch for lack of commits and ask developers to break into smaller tasks I believe in atomic check ins. However, without a “quiet period” the continuous server will keep rebuilding. Plus it makes it harder to say “this commit was for feature X” when really there were 10 such commits. I’ve often wondered about using Git locally to make these atomic commits and then checking them to SVN.

Weekly

Review tickets I usually review ones that are specific to the project I’m most working on more frequently than weekly.
Ask specific developers to plan large tasks Done by me.
Post team tasks completed and what is planned for the next week I can’t say we do this.

Bi-Weekly

Find developers interested in new projects We often are asked what sounds interesting to us and we try to pass that on when talking about features of a project.
Do “onboarding” Our tech lead did a great job with this a year ago when I joined his team. I’ve tried to create Eclipse templates that others can use. We would need to work on this more if we were expecting any developer to join the team.
Evaluate trial developers We don’t have any trial developers but we look at our current developers and assess them. If we don’t think they are working out, we are willing to try other developers.

So what does this mean? It means I’m already doing a lot that a tech lead should be doing, so I’d be totally comfortable taking that position. (Hint, hint, wink, wink, nudge, nudge.)

I was hoping for

def sayHello(name) {
  println("Hello, " + name)
}

("world", "Adam").foreach(sayHello)

but will have to settle for

def sayHello(name: String) {
  println("Hello, " + name)
}

List("world", "Adam").foreach(sayHello _)

I like Firefox. A lot. Even when it was named Phoenix.

I even use it at work (using PortableApps.com).

But some sites (ok, only StackExchange sites) I visit I get multiple popups asking for my user name and password. Because I’m behind a firewall I have to enter my credentials, no big deal. But they don’t work! So I have to hit Cancel. Not just once, but, like, 4 times!

View full article »

Since I don’t want to register with the site just to post a comment, I’ll leave it here.

To follow up with the discussion, you need to set your Spring config like so:

<bean id="quartzScheduler" class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
    <property name="triggers">
        <list>
            <ref bean="XXXXXXXXXXXXXXXXXXXX" />
            <ref bean="XXXXXXXXXXXXXXXXXXXX" />
        </list>
    </property>
    <property name="autoStartup">
        <value>${service.quartz.autostart}</value>
    </property>
    <property name="quartzProperties">
        <props>
            <prop key="org.quartz.scheduler.skipUpdateCheck">true</prop>
        </props>
    </property>
</bean>

Quartz ‘phoning home’ at start up.

From http://www.javacodegeeks.com/2011/07/top-97-things-every-programmer-or.html:
It’s never too early to think about performance – Rebecca Parsons

From Effective Java:
More computing sins are committed in the name of efficiency (without necessarily achieving it) than for any other single reason—including blind stupidity.

—William A. Wulf [Wulf72]

We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil.

—Donald E. Knuth [Knuth74]

We follow two rules in the matter of optimization:

Rule 1. Don’t do it.

Rule 2 (for experts only). Don’t do it yet—that is, not until you have a perfectly clear and unoptimized solution.

—M. A. Jackson [Jackson75]

When I started programming I thought the goal was to produce code that was fast. So I wrote concise code without regard for readability. Now, I lean toward readability. I guess I’m just trying to differentiate performance and optimization. Performance is good. (Premature) optimization is bad. I struggle with this because I find it easier and more enjoyable working with the details and not at a system level.

All views expressed here are of Adam Koch solely and do not represent his employer's.