Category Archives: Java/Java EE

The 8 Nights of Java – Night 2

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Continuing The 8 Nights of Java series, tonight we focus on Java 1.2. While Java 1.0 and 1.1 were about establishing a strong base and creating a set of classes that directly interfaced with operating system components, such as threads, Java 1.2 was focused on building on top of that base with convenient and reusable classes. For example, you could create your own dynamic array using the built-in primitive arrays, but do you really want to? Java 1.2 answered this by showing that Java was more than just a language, it was a useful set of reusable tools written by software developers, for software developers.

Jump to: [Night 1 | Night 2 | Night 3 | Night 4 | Night 5 | Night 6 | Night 7 | Night 8]

Java 1.2 Notable Features
Sun released Java 1.2 (codename Playground) on December 8, 1998. This version included:

  • Collections framework
  • Swing
  • Java Applet browser plug-in

From Jeanne:

Hard to believe the Collections framework has been with us for so long. It works. There’s lots of collections and opportunities for extension. And I’m thankful we don’t have a Collections2 or Collections3 framework. Something this core is useful to last unchanged. There have been Collection implementations added over time, but that makes sense because it is a framework. Even in Java 8, Oracle added static and default methods so they could leave the interfaces backward compatible.

As for the others. Well. I’ve written exactly one Swing program professionally. And I only did it because Console.readPassword() wasn’t available yet at that time. Unfortunately it is still with us. The wonders of “legacy code.” The Java browser plugin served its use. More recently, its contributed to feelings of Java being insecure though. It also contributed to some confusion between Java and JavaScript. I’ll never forget the day the help desk told me to reinstall Java to “solve” a JavaScript browser problem. Needless to say, I declined. And the problem was not related to Java after all. Gasp!

Fun fact: my very first Java program for school used Java 1.2.

From Scott:

I have to agree with Jeanne on this one. Although the Collections framework was a little difficult to use until generics were added in Java 5.0, they were from the start very powerful. I remember studying linked lists, hash maps, tree sets, and sorting in school. While all software developers should know these concepts and be able to implement them… in production software engineering it’s far better to go with a feature-rich implementation that has been written and tested by hundreds of developers than your own piecemeal solution (aka a “square wheel”).

As for Swing, I’ll be honest and say there was never a time I enjoyed programming in Swing. Even “back in the day” the Swing UI already looked quite dated. It was very difficult to write Swing code that looked good without relying on a number of often proprietary plugins, which required licenses to use. I remember registering for courses online (pilot program at the time, previous students had to do so in person) and a Swing app popped up within the browser, then promptly crashed 4-5 times in a row. I don’t know if the Swing apps I had the misfortune to use were just poorly written, poorly designed, or the underlying technology was just flawed. The one thing I do know is that I have never looked at a Swing app (either one that I’ve written or used) and thought it looked “beautiful” or was “easy to use”.

The limitation of Swing, as well as other Java UI languages, still holds true today in professional software development. While many people use Java for back-end systems, most use some flavor of Javascript (Angular, Node.js, Ajax) or mobile design tool (xib, storyboard, view, layout) for the majority of their front-end work. Even JavaFX, which was later billed as the “greatest Java UI language since Swing” was never able to gain much ground, in part because so many developers carried over a dislike of Swing. I do wonder how Java would be different today, if Swing had been easier to use and looked nicer.

The 8 Nights of Java – Night 1

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Given the holiday season, we thought it would be fun to share our favorite (or least favorite) features from all 8 versions of Java that have been released to date. Some features, like generics and autoboxing/unboxing, were met with a lot of fanfare and have since changed the way we as developers write code. Others, like NIO.1 and RMI, are not nearly as popular today as originally envisioned. With that in mind, we’ll be posting one entry each night on a different version of Java, starting tonight with Java 1.

Oh, we want to wish all of our readers a Happy and Healthy Holiday, as well as a Wonderful New Year!

Jump to: [Night 1 | Night 2 | Night 3 | Night 4 | Night 5 | Night 6 | Night 7 | Night 8]

Java 1.0/1.1 Notable Features
Sun introduced Java 1.0 (codename Oak) on January 23, 1996, with a more stable Java 1.1 released in February of the following year. These versions included:

  • Compiler and JVM runtime environment
  • JDBC
  • The beginnings of reflection
  • Inner classes
  • Thread class

From Scott:

Java 1.0 released.. well, Java! We all take for granted the ability to execute Java code on nearly every platform but back when Java was first released the idea of compiling source code into byte code and running inside a virtual machine was absolutely revolutionary. It was one of the first languages to allow developers to work freely in any environment and deploy to any other environment. Before Java, programmers tended to use the same operating system, same IDE software, and same compiler to write software that often could only run on a handful of environments. Java helped foster the open source movement allowing developers to work in Linux, Windows, MacOS, etc and deploy to any system. At a time when hardware and software systems were much more heterogeneous than they are today, Java helped improve productivity and sharing across a wide variety of landscapes.

Of course, early on there were some problems. Microsoft released Visual J++ alongside Sun’s implementation which contained only a subset of Sun’s features, as well as additional features Microsoft wrote themselves. These differences almost splintered the Java landscape within the first few years, since Visual J++ was so different from Sun’s implementation. Luckily for us, Sun intervened, successfully suing Microsoft on the basis that it violated Sun’s license agreement by releasing a version of Java not compatible with other versions of Java, helping to solidify Java as a standards-based language. In hindsight, articles like “Microsoft’s J/Direct called death of Java” written in 1997 (and comical now) would be the first of many (including a famous interview with Steve Jobs) to incorrectly predict Java’s demise. Today, Java is used in over 3 billion devices worldwide.

My favorite part of Java 1.0? The fact that the Thread class was included right away. Multi-threaded programming was still somewhat new, especially since multi-core processors were still in their infancy. Providing a new language in which developers could process tasks in parallel was pretty forward thinking, even if our thread-base implementations weren’t always perfect. Today, we tend to rely on the Concurrency API given its feature-rich convenience and stability, but never forget it’s is built entirely upon the Thread class.

From Jeanne:

Version 1.0 included Vector. While we no longer use Vector for new code, it paved the way for ArrayList and the Collections framework. JDBC is one of my favorite libraries. I use a mix of raw JDBC, ORM and Spring JDBC template these days, but JDBC started all of this. And then we have the parts of the language that stood the test of time. Plus since Sun/Oracle find it hard to actually get rid of anything from the language, we also have such fond deprecated memories such as Date’s getHours() methods. I was still in high school when Java 1 launched. I never actually worked with it directly as Java 1.2 was out before I started even reading about Java. When Java turned 10, it was cool to read Hello World(s) – From Code to Culture and see how Java got started. Or should I say how Oak got started?

OCP 8 – working with autocommit vs savepoints

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You might want to know more about JDBC than is covered by Chapter 10 of our book, OCP: Oracle Certified Professional Java SE 8 Programmer II Study Guide: Exam 1Z0-809. This blog post teaches you about autocommit and savepoints and assumes you have completed reading chapter 10 of our OCP 8 book and are looking to learn more. (Note: we’ve heard rumors this topic is in fact on the exam. It wasn’t when we took the beta but was on the Java 7 exam. So either the questions are left over or it was added back.)

In the book, you saw how to run one statement at a time and have the database automatically see the changes right away. This is called automatic commit or auto-commit for short. A commit updates the database. JDBC provides options for more control by running your code in transactions. A transaction allows a group of statements to go together.

Rollback/Commit

By default, auto-commit is set to true which means each statement is committed in the database as soon as it is run. You can set it to false so statements and prepared statements do not automatically commit data.

The following example gives that control. If anything goes wrong update either of the rows, the entire transaction is rolled back and the database doesn’t change either row. If both are successful, the database sees both.

conn.setAutoCommit(false);
String sql = "update species name = ? where id = ?";
PreparedStatement ps = conn.prepareStatement(sql);
try {
  ps.setString(1, "Elephant");
  ps.setInt(2, 1);
  ps.executeUpdate();
  ps.setString(1, "Monkey");
  ps.setInt(2, 4);
  ps.executeUpdate();
  
  conn.commit();      // send data to database
} catch (SQLException e) {
  conn.rollback();    // don't update database
}

Let’s rewrite this example to focus more on the commit/rollback code:

conn.setAutoCommit(false);
String sql = "update species name = ? where id = ?";
PreparedStatement ps = conn.prepareStatement(sql);
try {
  updateRecord(1);
  updateRecord(2);
  conn.commit(); // send data to database 
} catch (SQLException e) {
  conn.rollback(); // don't update database 
}

Setting a Rollback point

JDBC has a type called a Savepoint which is like putting a bookmark in a book so you can easily get back there.

conn.setAutoCommit(false);
String sql = "update species name = ? where id = ?";
PreparedStatement ps = conn.prepareStatement(sql);
try {
  updateRecord(1);
  Savepoint sp = conn.setSavepoint();
  updateRecord(2);
  updateRecord(3);
  // oops - let's go back like this didn't happen
  conn.rollback(sp);
  // proceed from there
  updateRecord(4);
  conn.commit(); // send data to database 
} catch (SQLException e) { 
  conn.rollback(); // don't update database 
}