java

We recently upgraded from Java 8 to openjdk16. And our webservice clients failed with below error. Failed to execute goal org.jvnet.jax-ws-commons:jaxws-maven-plugin:2.3:wsimport (MyWebServiceClient) on project com.myproject: Execution MyWebServiceClient of goal org.jvnet.jax-ws-commons:jaxws-maven-plugin:2.3:wsimport failed: start 0, end -1, length 0 -> [Help 1] And the fix was to change the plugin for ws-import. Before we had  <groupId>org.jvnet.jax-ws-commons</groupId><artifactId>jaxws-maven-plugin</artifactId><version>2.3</version> And … Read more

While upgrading from hibernate 3 to hibernate 5, this was one of the issues. Here is how id fields were defined in hibernate 3. @Id@GeneratedValue(strategy=GenerationType.AUTO, generator=”my_seq_gen”)@SequenceGenerator(name=”my_seq_gen”, sequenceName=”MY_SEQ”)private long id; So now, I added allocationSize = 1 to resolve the issue @Id@GeneratedValue(strategy=GenerationType.AUTO, generator=”my_seq_gen”)@SequenceGenerator(name=”my_seq_gen”, sequenceName=”MY_SEQ”, allocationSize = 1)private long id; And for new Ids I used the … Read more

This turned out to be a mistake in the config.  I was using mysql driver. It was a copy-paste mistake. <bean id=”dataSource” class=”org.apache.commons.dbcp2.BasicDataSource”destroy-method=”close”><property name=”driverClassName”><value>com.mysql.jdbc.Driver</value></property>   Here is the correct config: <bean id=”dataSource” class=”org.apache.commons.dbcp2.BasicDataSource”destroy-method=”close”><property name=”driverClassName”> <value>org.postgresql.Driver</value></property>   And the postgres entry in pom.xml : <dependency><groupId>org.postgresql</groupId><artifactId>postgresql</artifactId><version>42.2.23</version></dependency>

Resolving Spring Context Initialization Error: NoClassDefFoundError for ValidatorFactory The root cause of this issue is a java.lang.NoClassDefFoundError for the javax/validation/ValidatorFactory class. This error usually occurs when there’s a missing dependency in your project. In this case, it’s likely that you’re missing the Java Validation API (JSR 303) dependency. To resolve this issue, you need to … Read more

On upgrading Hibernate from version 3 to version 5, I got the above error. Turned out that we were also using Mockito and it also has a dependency on byte buddy. So there was conflict of versions of byet buddy. So here is fix: <dependency><groupId>org.mockito</groupId><artifactId>mockito-core</artifactId><version>2.2.28</version><scope>test</scope><exclusions><exclusion><groupId>net.bytebuddy</groupId><artifactId>byte-buddy</artifactId></exclusion></exclusions></dependency> exclude the byte-buddy jar from mockito.    

Recently we needed to reindex our data due to some changes. Here is how we did it. We defined a file on the file system. If that file is present the reindexing thread runs, so it would easy for our deployment team to run reindexing when needed. Here is the code creating the thread.  So … Read more

Recently we ended up in an issue with enums. One of the developers changed the order of enums because of a change he had to do. And he thought that enum values that are logically together should be put together in enum class also. But when he was done with the change, all the tests … Read more

Have you ever come across a situation that you need to do rate limiting to an api.  In this article we look at one of the ways rate limiting can be done. We would limit access to an api and make only 1 call to api within 2 seconds. This class would use threads and … Read more

In Java scheduling a task to run on fix intervals is quite simple.  Here is the code to create a scheduler