Colleagues gave me "Thinking in Java, 3rd" and Shhgs users' translation before the first eleven chapters, it is true. The first chapter is about object-oriented and Java features, as if the first chapter of foreigners is this characteristic, some simply call Chapter 0. However, I have seen these, I always feel very empty, there is no practical thing, so I still read the book. Here is a simple record of some of the content learned today.
The main features of Java language: Java is a simple, cross-platform, object-oriented, distributed, semi-compiled, strong, safe, excellent, multi-threaded, dynamic language. (It seems that there is only one sentence, but every adjective can come out and say a big one.)
Comparison of Java and C and C : 1. Automatic memory management: Java is dynamic for memory allocation, and has garbage collection mechanisms. 2, not defined global variables outside the class. 3. The GOTO statement will no longer be used in Java. 4, the pointer is canceled in Java. 5, support the data type of the fixed bit number. 6. Runtime system Type Conversion Type Compatibility Check 7, Java does not support header files, using IMPORT and other types of communication. 8, Java does not include structural and union, all content is packaged in the class. 9. The macro is not supported in Java. It declares a constant through the Final keyword. 10. Java does not support multiple inheritance, which can achieve multiple inheritance functions through interfaces in Java. I am studying C . Today, I started learning Java is not because Java is better than C , but because Java's application is too wide, I have experienced deeper, so I learned Java because I need to learn it.
JDK Development Environment Tools: 1. Java Compiler (JavaC.exe): Converting the Java Source Code File (.java) into a bytepode code file (.class). 2, Java Interpreter (Java.exe): The bytecode used to perform JAVAC compile. 3, Java Applet browser (AppletViewer.exe): Perform Java browser for Java applets on HTML files. 4, Java Document Builder (JavaDoc.exe): Generates a set of HTML formats using the Java source file code. 5, Java Debugger: It is an extension that provides a command line debugging environment for Java programs to facilitate the unscrupulous class for Java interpretation. 6, Java Antiobo (JavaP.exe): Absorbed a Java byte code file, returning to the class.
AppletViewer is a bit problem, there is a wrong error -------------------- I am underline ------------------------------------------------ --- E: / mywork / java / practice / sub01> appletviewer Hello.htmlException in thread "main" java.util.MissingResourceException: Can not find resource for bundle sun.applet.resources.MsgAppletViewer, key appletpanel.badattribute.exceptionat java.util.ResourceBundle.getObject (ResourceBundle.java:314) at java.util.ResourceBundle.getObject (ResourceBundle.java:311) at java.util.ResourceBundle.getString (ResourceBundle.java:274) at sun.applet.AppletMessageHandler .getMessage (AppletMessageHandler.java:39) at sun.applet.AppletPanel.showAppletStatus (AppletPanel.java:701) at sun.applet.AppletPanel.init (AppletPanel.java:185) at sun.applet.AppletViewer.
At sun.applet.appletviewer.parse (appletViewer.java: 1062) at sun.applet.appletViewer.Parse (AppletViewer.java: 996) at sun.applet.main.run (main.java: 138) at sun.applet. Main.Main (main.java:80) -------------------- I am also underline ----------------- --- I guess because it is the first time IMPORT, there may be problems with possible environment variables. Wait a look, look at the previous Java lectures. Below this sentence is quite interesting. JavaScript (Which Has Nothing to do with java; it's named that way just to grab home of java's marketing momentum)
