Certifications are a great way to learn new technologies and to get proficient at the technologies that you already know. The exam objectives are designed by experts and include topics that one should master for a given field. This allows you to optimize your time by focusing on the important stuff.
If you are a Java professional, there are several certifications available that help you to increase your worth for your employer and/or help you find a job.
The first and foremost certification that you should get is the Oracle Certified Professional Java Programmer Certification. This certification is important because it makes sure that you are clear on the basics of Java programming.
Once you have nailed the basics of Java programming, you can either go for Amazon Web Services (AWS) certifications or Data Analytics certifications provided by various companies such as Cloudera and Apache. These are administered by Certified Data Management Professional (CDMP) certifications and also by Open CDS.
Most enterprise Java projects use some component of Spring Framework. If you or your company is willing to spend money for Spring training, you can go for Spring Certification administered by VMware/Pivotal.