When you work with JAXB to generate Java code from XSD (or *ghasp* WSDL) files, you're going to use the XJC tool, which is shipped with the JDK (at least until JDK 9 - with Jigsaw, it will soon be externalised into its own external dependency). Adding plugins to XJC when running it via Maven … Continue reading How to Implement Your Own XJC Plugin to Generate toString(), equals(), and hashCode() Methods
Category: java
This category contains posts about things that are essentially Java-related
How to Fetch Oracle DBMS_OUTPUT from JDBC
When working with Oracle stored procedures, it is not uncommon to have debug log information available from DBMS_OUTPUT commands. For instance, if we have a procedure like this: CREATE TABLE my_table (i INT); CREATE OR REPLACE PROCEDURE my_procedure (i1 INT, i2 INT) IS BEGIN INSERT INTO my_table SELECT i1 FROM dual UNION ALL SELECT i2 … Continue reading How to Fetch Oracle DBMS_OUTPUT from JDBC
A Common Mistake Developers Make When Caching Nullable Values
Caching is hard in various ways. Whenever you're caching things, you have to at least think of: Memory consumption Invalidation In this article, I want to show a flaw that often sneaks into custom cache implementations, making them inefficient for some execution paths. I've encountered this flaw in Eclipse, recently. What did Eclipse do wrong? … Continue reading A Common Mistake Developers Make When Caching Nullable Values
How to Ensure Your Code Works With Older JDKs
jOOQ is a very backwards compatible product. This doesn't only mean that we keep our own API backwards compatible as well as possible, but we also still support Java 6 in our commercial distributions. In a previous blog post, I've shown how we manage to support Java 6 while at the same time not missing … Continue reading How to Ensure Your Code Works With Older JDKs
Using JDK 10’s Local Variable Type Inference with jOOQ
After the successful release of JDK 9, we can already look forward, and play around with early access releases of JDK 10. The list of JEPs currently targeted for JDK 10 is quite manageable so far. JEP 286 is probably the most exciting one for most Java developers: Local variable type inference (which we've blogged … Continue reading Using JDK 10’s Local Variable Type Inference with jOOQ
Squeezing Another 10% Speed Increase out of jOOQ using JMC and JMH
In this post, we're going to discuss a couple of recent efforts to squeeze roughly 10% in terms of speed out of jOOQ by iterating on hotspots that were detected using JMC (Java Mission Control) and then validated using JMH (Java Microbenchmark Harness). This post shows how to apply micro optimisations to algorithms where the … Continue reading Squeezing Another 10% Speed Increase out of jOOQ using JMC and JMH
Benchmarking JDK String.replace() vs Apache Commons StringUtils.replace()
What's better? Using the JDK's String.replace() or something like Apache Commons Lang's Apache Commons Lang's StringUtils.replace()? In this article, I'll compare the two, first in a profiling session using Java Mission Control (JMC), then in a benchmark using JMH, and we'll see that Java 9 heavily improved things in this area. Profiling using JMC In … Continue reading Benchmarking JDK String.replace() vs Apache Commons StringUtils.replace()
jOOQ 3.10 Supports JPA AttributeConverter
One of the cooler hidden features in jOOQ is the JPADatabase, which allows for reverse engineering a pre-existing set of JPA-annotated entities to generate jOOQ code. For instance, you could write these entities here: @Entity public class Actor { @Id @GeneratedValue(strategy = IDENTITY) public Integer actorId; @Column public String firstName; @Column public String lastName; @ManyToMany(fetch … Continue reading jOOQ 3.10 Supports JPA AttributeConverter
A Curious Java Language Feature and How it Produced a Subtle Bug
Java's visibility rules are tricky at times. Do you know what this will print? package p; import static p.A.x; class A { static String x = "A.x"; } class B { String x = "B.x"; } class C { String x = "C.x"; class D extends B { void m() { System.out.println(x); } } } … Continue reading A Curious Java Language Feature and How it Produced a Subtle Bug
Don’t Overdo the “Principle of Least Astonishment” Cargo Cult
As we all agree, GOTO is evil, right? Relevant XKCD Or even funnier: New Intern Knows Best Of course, GOTO isn't evil Of course, somewhere deep down in our professional selves, we know that GOTO isn't evil, it's just a very basic processor instruction that was available since the early days of assembly code. GOTO … Continue reading Don’t Overdo the “Principle of Least Astonishment” Cargo Cult