I was simply assuming the need for Java install was based on the use of Facebook without the requirement of this fella's internet usage, not what elements of a computer use Java, but seeing as we need to get anal about it :

Java Platform

Main articles: Java (software platform) and Java Virtual Machine
One characteristic of Java is portability, which means that computer programs written in the Java language must run similarly on any supported hardware/operating-system platform. This is achieved by compiling the Java language code to an intermediate representation called Java bytecode, instead of directly to platform-specific machine code. Java bytecode instructions are analogous to machine code, but are intended to be interpreted by a virtual machine (VM) written specifically for the host hardware. End-users commonly use a Java Runtime Environment (JRE) installed on their own machine for standalone Java applications, or in a Web browser for Java applets.
Standardized libraries provide a generic way to access host-specific features such as graphics, threading, and networking.
A major benefit of using bytecode is porting. However, the overhead of interpretation means that interpreted programs almost always run more slowly than programs compiled to native executables would. Just-in-Time compilers were introduced from an early stage that compile bytecodes to machine code during runtime. Over the years, this JVM built-in feature has been optimized to a point where the JVM's performance competes with natively compiled C code.[citation needed]
[edit] Implementations

Sun Microsystems officially licenses the Java Standard Edition platform for Linux,[21] Mac OS X,[22] and Solaris. Although in the past Sun has licensed Java to Microsoft, the license has expired and has not been renewed.[23] Through a network of third-party vendors and licensees,[24] alternative Java environments are available for these and other platforms.
Sun's trademark license for usage of the Java brand insists that all implementations be "compatible". This resulted in a legal dispute with Microsoft after Sun claimed that the Microsoft implementation did not support RMI or JNI and had added platform-specific features of their own. Sun sued in 1997, and in 2001 won a settlement of US$20 million, as well as a court order enforcing the terms of the license from Sun.[25] As a result, Microsoft no longer ships Java with Windows, and in recent versions of Windows, Internet Explorer cannot support Java applets without a third-party plugin. Sun, and others, have made available free Java run-time systems for those and other versions of Windows.
Platform-independent Java is essential to the Java EE strategy, and an even more rigorous validation is required to certify an implementation. This environment enables portable server-side applications, such as Web services, Java Servlets, and Enterprise JavaBeans, as well as with embedded systems based on OSGi, using Embedded Java environments. Through the new GlassFish project, Sun is working to create a fully functional, unified open source implementation of the Java EE technologies.
Sun also distributes a superset of the JRE called the Java Development Kit (commonly known as the JDK), which includes development tools such as the Java compiler, Javadoc, Jar, and debugger.
[edit] Performance

Main article: Java performance
Programs written in Java have a reputation for being slower and requiring more memory than those written in C.[26] However, Java programs' execution speed improved significantly with the introduction of Just-in-time compilation in 1997/1998 for Java 1.1,[27][28] the addition of language features supporting better code analysis (such as inner classes, StringBuffer class, optional assertions, etc.), and optimizations in the Java Virtual Machine itself, such as HotSpot becoming the default for Sun's JVM in 2000.
To boost even further the speed performances that can be achieved using the Java language, Systronix made JStik,[29] a microcontroller based on the aJile Systems[30] line of embedded Java processors. In addition, the widely used ARM family of CPUs has hardware support for executing Java bytecode through its Jazelle option.