You shouldn't worry too much about the many technologies there are to learn. There are just too many for one person to know.
Pick a few and concentrate on those. Familiarity with Spring, JDBC/ORM, JMS.
web services and technologies like Javascript (JQuery, node.js), HTML5, CSS will give you good general, cross-functional knowledge and adaptability.
Basic knowledge of tools like Git, Subversion, Maven, Gradle, JUnit, and mocking frameworks are also useful because they make you a more productive developer.
One thing that might set you apart from other entry-level candidates is a familiarity with Agile software development techniques.
Knowledge of Test-Driven Development is becoming more and more something that I look for when I do interviews.
I don't really look for knowledge in specific technologies when I interview junior level candidates.
What I look for is a basic understanding of principles: Object-orientation, design, testing. You should have good programming habits.
Read "Clean Code" by Robert Martin to get an idea of what I'm talking about. I also try to see how well they will work with others (you'll do that a lot of that if you're a junior developer) and I like it when they are open to coaching and mentoring.
The candidates who show an eagerness to learn and an ability to pick up on things that I teach them during an interview (I do something that's really more of an audition rather than an interview) are the ones who I am more likely to consider for the job.
Here is the list of Java web frameworks that we’ll be comparing listed alphabetically:
Dropwizard
Grails
GWT
JHipster
JSF
Play framework
Spring Boot
Spring MVC
Struts
Vaadin
Hibernate