java tips - Chapter 1 Introduction to Java Brief History of...

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Unformatted text preview: Chapter 1 Introduction to Java Brief History of the Java Language Java began as a research project inside Sun Microsystems and developed by James gosling since 19 First released was in 1995 (java 1.0) which interested a bout what is known "web app " After no much time many of browsers support j In spite of success of java , problems began be noticed with elementary versions because of (1) a lot of (Bugs) that j continue, and (2) java has limited capabilities (250 classes) (3) deep slow in implementat In 1998 java was developed drastically through (1) The language syntax which derives much of its from C and C++ has a simpler object derives much of its from C and C++ but has a simpler object , (2) fu object-oriented,(3) Dynamic Memory Management (Garbage Collection), (4 ) "applications that are independent of hardware and operating systems?" It means you can compile a Java program on any system and run the resulting bin executable file on the same or any other syst How does java work At the beginning we write a source code file(.java) containing instructions of java , then passes it to the compiler wh ensures the file is free of error and build a new bytecode file (.class) which is independent on any platform will implem un Java structure Text-printing program 1 // 2 // Text-printing program . 3 4 public class Welcome1 5 } 6 // main method begins execution of Java application 7 public static void main( String args ( 8 } 9 System.out.println( "Welcome to Java Programming ;( "! 10 11 // { end method main 12 13 // { end class Welcome1 Welcome to Java Programming ! Text-printing program illustration // indicating that the remainder of the line is a comment : // single – line comment */ multiple Line coment /* class declaration Every program in Java consists of at least one class declaration that is defined by the programmer These are known as programmer-defined classes or user- defined classes The class keyword introduces a class declaration in Java and is immediately followed by the class name ( Welcome1 ). Keywords (sometimes called reserved words ) are reserved for use by Java By convention, all class names in Java begin with a capital letter and capitalize the first letter of each word they include (e.g., SampleClassName ). A Java class name is an identifier a series of characters consisting of letters, digits, underscores ( _ ) and dollar signs ( $ ) that does not begin with a digit and does not contain spaces Some valid identifiers are Welcome1, $value, _value, m_inputField1 and button7 . The name 7button is not a valid identifier because it begins with a digit, and the name...
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This note was uploaded on 11/14/2011 for the course MATH 401 taught by Professor H.ayad during the Spring '11 term at Cairo University.

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java tips - Chapter 1 Introduction to Java Brief History of...

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