Java is a simple language. Java was initially modeled after C and C++, minus some potentially confusing features. Pointers, multiple implementation inheritance, and operator overloading are some C/C++ features that are not part of Java. A feature not mandated in C/C++, but essential to Java, is a garbage-collection facility that automatically reclaims objects and arrays. Java is an object-oriented language. Java's object-oriented focus lets developers work on adapting Java to solve a problem, rather than forcing us to manipulate the problem to meet language constraints. This is different from a structured language like C. For example, whereas Java lets you focus on savings account objects, C requires you to think separately about savings account state (such a balance) and behaviors (such as deposit and withdrawal). Java is a network-savvy language. Java's extensive network library makes it easy to cope with Transmission Control Protocol/Internet Protocol (TCP/IP) network protocols like HTTP (HyperText Transfer Protocol) and FTP (File Transfer Protocol), and simplifies the task of making network connections. Furthermore, Java programs can access objects across a TCP/IP network, via Uniform Resource Locators (URLs), with the same ease as you would have accessing them from the local file system. Java is an interpreted language. At runtime, a Java program indirectly executes on the underlying platform (like Windows or Linux) via a virtual machine (which is a software representation of a hypothetical platform) and the associated execution environment. The virtual machine translates the Java program's bytecodes (instructions and associated data) to platform-specific instructions through interpretation. Interpretation is the act of figuring out what a bytecode instruction means and then choosing equivalent "canned" platform-specific instructions to execute. The virtual machine then executes those platform-specific instructions. Interpretation makes it easier to debug faulty Java programs because more compile-time information is available at runtime. Interpretation also makes it possible to delay the link step between the pieces of a Java program until runtime, which speeds up development. Java is a robust language. Java programs must be reliable because they are used in both consumer and mission-critical applications, ranging from Blu-ray players to vehicle-navigation or air-control systems. Language features that help make Java robust include declarations, duplicate type checking at compile time and runtime (to prevent version mismatch problems), true arrays with automatic bounds checking, and the omission of pointers. (We will discuss all of these features in detail later in this series.) Another aspect of Java's robustness is that loops must be controlled by Boolean expressions instead of integer expressions where 0 is false and a nonzero value is true. For example, Java doesn't allow a C-style loop such as while (x) x++; because the loop might not end where expected. Instead, you must explicitly provide a Boolean expression, such as while (x != 10) x++; (which means the loop will run until x equals 10).