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Debugging Java version issues

1. Error: Unsupported major.minor version 51.0 error?

What does this error mean?

The above error means what version of the JRE that the class file is compatible with. “org/apache/cxf/management/annotation/ManagedResource” was compiled with based on the following

So, “51” means it is compatible with “J2SE 7 “.

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Debugging Certificates do not conform to algorithm constraints

Why? You may have a certificate with SHA1RSA key size less than 1024 bits or you have a certificate in your chain that uses MD2RSA.

Explanation? MD2 was widely recognized as insecure and thus disabled in Java in version JDK 7 onwards.

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Debugging like a pro with eclipse IDE tutorial for Java developers

Often you get to work on a fully functional Java application that is already in production to fix production issues or to enhance its existing functionality. As a new Java developer in the team, it is not easy to get started and contributing. The approach would be slightly different from working on a brand new project.

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Debugging LinkageErrors in Java

What is a LinkageError in Java?

A jar that is being loaded by two different classloaders can throw a java.lang.LinkageError. For example, your application server (e.g JBoss) on startup loads that jar or has a directory with that jar. Also, your EAR or WAR you are deploying has that jar in its say WEB-INF/lib.

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Debugging Spark applications written in Java locally by connecting to HDFS, Hive and HBase

This extends Remotely debugging Spark submit Jobs in Java. Running Spark in local mode When you run Spark in local mode, both the Driver and Executor will be running in the same JVM and is very handy to debug the logic of your transformations. … Read more ›...

Debugging SSL issues in Java & tools to debug

Q1. What are some of the issues you encounter with SSL handshake? A1. Some of the issues you try to debug are Presence of a valid certificate in trust store Incorrect certificate chains in the client or server truststore Invalid key algorithm used for private keys Expired certificate Incorrect passwords...

Finding your way around YARN and Spark on Cloudera

What is Apache Hadoop YARN? Apache Hadoop YARN (Yet Another Resource Negotiator) is the prerequisite for Enterprise Hadoop for dynamic allocation oc the cluster resources. For example, when you run a Spark job on YARN as opposed to in standalone mode, you can will take advantage of categorizing, isolating, and...

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Java Interview FAQs

800+ Java Interview Q&As