Security is a key aspect in Java programming language. Here are a few important areas of security to consider when working with Java:

1. The Java Sandbox: Java was designed with a built-in security model that confines certain activities of Java programs to a “sandbox”. It is an environment that allows code to be executed with a set of specific permissions. This model prevents untrusted code from accessing resources on the system it’s running on, like the file system or the network.

2. The Java Security Manager: This is a key component of the Java security model. The Security Manager acts as a gatekeeper, allowing or denying various operations (like reading or writing to the file system, or opening a network socket) based on the security policy in place.

3. Java Cryptography Architecture (JCA): This is a set of APIs for cryptographic services such as message digests, digital signatures, and encryption. This is a part of the standard Java class library.

4. Java Authentication and Authorization Service (JAAS): This API supports authentication and authorization for Java applications. It provides a way for applications to authenticate and enforce access controls upon users.

5. Transport Layer Security (TLS): Java supports the use of TLS to secure communications between two parties (e.g. between a client and server). It’s a protocol for securing communication over a network.

6. Java Certificates and KeyStore: Java provides a way to manage cryptographic keys and certificates via KeyStore and TrustStore, which are secure storage facilities for cryptographic keys and certificates.

7. Secure Coding Practices: As with any programming language, writing secure code is key. This includes avoiding common security pitfalls like SQL injection, cross-site scripting, and insecure deserialization, among others.