Iuliana Cosmina

In Chapter 4, a lot of Java code was written, but when designing classes, only the most simple da... more In Chapter 4, a lot of Java code was written, but when designing classes, only the most simple data types were used: a few numeric ones and text. In the JDK, a lot of data types are declared for a multitude of purposes: for modelling calendar dates, for representing multiple types of numeric, for manipulating texts, collections, files, database connections, and so forth. Aside from JDK, there are libraries created by other parties that provide even more functionality. But the data types provided by the JDK are fundamental ones, the bricks every Java application is built from. Of course, depending on the type of application you are building, you might not need all of them. For example, I've never had the occasion to use the java.util.logging.Logger class. Most applications that I've worked on were already set up by a different team when I came along, and they were using external libraries like Log4j or Logback, or logging abstractions like Slf4j. This section covers the basic Java data types that you need to write about 80% of any Java application. Stack and Heap Memory Java types can be split in two main categories: primitive and reference types. Java code files are stored on the HDD, Java bytecode files as well. Java programs run on the JVM, which is launched as a process by executing the java executable. During execution, all data is stored in two different types of memory named: stack and heap that are allocated for a program's execution by the operating system. The stack memory is used during execution(also referred to as at runtime) to store method primitive local variables and references to objects stored in the heap. A stack is also a data-structure represented by a list of values that can only be accessed at one

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Implementing Controllers: Advanced