{"id":181,"date":"2020-12-04T17:42:18","date_gmt":"2020-12-04T17:42:18","guid":{"rendered":"http:\/\/bhtinstitute.com\/knowhow\/?p=181"},"modified":"2020-12-04T17:42:33","modified_gmt":"2020-12-04T17:42:33","slug":"ii-get-started-with-java-programming","status":"publish","type":"post","link":"http:\/\/bhtinstitute.com\/knowhow\/ii-get-started-with-java-programming\/","title":{"rendered":"II – Get Started with Java Programming"},"content":{"rendered":"\n

1.  How To Install JDK on Windows<\/h3>\n\n\n\n

Step 0: Un-Install Older Version(s) of JDK\/JRE<\/h5>\n\n\n\n

I recommend that you install only the latest<\/em> JDK. Although you can install multiple versions of JDK\/JRE concurrently, it is messy.<\/p>\n\n\n\n

If you have previously installed older version(s) of JDK\/JRE, un-install ALL of them. Goto “Control Panel” \u21d2 (optional) “Programs” \u21d2 “Programs and Features” \u21d2 Un-install ALL programs begin with “Java”, such as “Java SE Development Kit …”, “Java SE Runtime …”, “Java X Update …”, and etc.<\/p>\n\n\n\n

Step 1: Download JDK<\/h5>\n\n\n\n
  1. Goto Java SE download site @ http:\/\/www.oracle.com\/technetwork\/java\/javase\/downloads\/index.html<\/a>.<\/li>
  2. Under “Java Platform, Standard Edition” \u21d2 “Java SE 13.0.{x}”, where {x} denotes a fast running security-update number \u21d2 Click the “Oracle JDK Download” button.<\/li>
  3. Under “Java SE Development Kit 13.0.{x}” \u21d2 Check “Accept License Agreement”.<\/li>
  4. Choose the JDK for your operating system, i.e., “Windows”. Download the “exe<\/strong>” installer (e.g., “jdk-13.0.{x}_windows-x64_bin.exe<\/strong><\/code>” – about 159MB).<\/li><\/ol>\n\n\n\n
    Step 2: Install JDK<\/h5>\n\n\n\n

    Run the downloaded installer (e.g., “jdk-13.0.{x}_windows-x64_bin.exe<\/code>“), which installs both the JDK and JRE.<\/p>\n\n\n\n

    By default, JDK is installed in directory “C:\\Program Files\\Java\\jdk-13.0.{x}<\/code>“, where {x}<\/code> denotes the update number. Accept the defaults and follow the screen instructions to install JDK.<\/p>\n\n\n\n

    Use your “File Explorer”, navigate to \"C:\\Program Files\\Java\"<\/code> to inspect the sub-directories. Take note of your JDK installed directory<\/strong> jdk-13.0.{x}<\/code>, in particular, the update number {x}<\/code>, which you will need in the next step.<\/p>\n\n\n\n

    I shall refer to the JDK installed directory<\/strong> as <JAVA_HOME><\/code><\/strong>, hereafter, in this article.<\/p>\n\n\n\n

    Step 3: Include JDK’s “bin” Directory in the PATH<\/h5>\n\n\n\n

    Windows’ Command Prompt (CMD<\/code>) searches the current directory and the directories listed in the PATH<\/code> environment variable<\/em> (or system variable<\/em>) for executable programs. JDK’s programs (such as Java compiler \"javac.exe<\/code>” and Java runtime \"java.exe<\/code>“) reside in the sub-directory<\/em> “bin<\/code>” of the JDK installed directory. You need to include JDK’s “bin<\/code>” in the PATH<\/code> to run the JDK programs.<\/p>\n\n\n\n

    To edit the PATH<\/code> environment variable in Windows 10:<\/p>\n\n\n\n

    1. Launch “Control Panel” \u21d2 (Optional) “System and Security” \u21d2 “System” \u21d2 Click “Advanced system settings” on the left pane.<\/li>
    2. Switch to “Advanced” tab \u21d2 Click “Environment Variables” button.<\/li>
    3. Under “System Variables” (the bottom pane), scroll down to select variable “Path” \u21d2 Click “Edit…”.<\/li>
    4. For Newer Windows 10<\/strong>:
      You shall see a TABLE<\/strong> listing all the existing PATH entries (if not, goto next step). Click “New” \u21d2 Click “Browse” and navigate to your JDK’s “bin<\/code>” directory, i.e., “c:\\Program Files\\Java\\jdk-13.0.{x}\\bin<\/strong><\/code>“, where {x}<\/code> is your installation update number \u21d2 Select “Move Up” to move this entry all the way to the TOP.<\/li>
    5. For Older Windows 10<\/strong> (Time to change your computer!):
      (CAUTION: Read this paragraph 3 times before doing this step! Don’t push “Apply” or “OK” until you are 101% sure. There is no UNDO!!!)<\/strong>
      (To be SAFE, copy the content of the “Variable value” to Notepad before changing it!!!)
      In “Variable value” field, APPEND “c:\\Program Files\\Java\\jdk-13.0.{x}\\bin<\/code>” (where {x}<\/code> is your installation update number) IN FRONT of all the existing directories, followed by a semi-colon (;<\/code>) to separate the JDK’s bin directory from the rest of the existing directories. DO NOT DELETE any existing entries; otherwise, some existing applications may not run.Variable name : PATH<\/strong> Variable value : c:\\Program Files\\Java\\jdk-13.0.{x}\\bin;<\/strong>[do not delete exiting entries…<\/em>]<\/strong><\/li><\/ol>\n\n\n\n

      Note: If you have started CMD, you need to re-start for the new environment settings to take effect.<\/p>\n\n\n\n

      Step 4: Verify the JDK Installation<\/h5>\n\n\n\n

      Launch a CMD<\/code> via one of the following means:<\/p>\n\n\n\n

      1. Click “Search” button \u21d2 Type “cmd” \u21d2 Choose “Command Prompt”, or<\/li>
      2. Right-click “Start” button \u21d2 run… \u21d2 enter “cmd”, or<\/li>
      3. Click “Start” button \u21d2 Windows System \u21d2 Command Prompt<\/li><\/ol>\n\n\n\n

        Issue the following commands to verify your JDK installation:<\/p>\n\n\n\n

        1. Issue “path<\/code>” command to list the contents of the PATH<\/code> environment variable. Check to make sure that your JDK’s “bin<\/code>” is listed in the PATH<\/code>.path<\/strong> PATH=c:\\Program Files\\Java\\jdk-13.0.{x}\\bin;other entries…<\/li>
        2. Issue the following commands to verify that JDK\/JRE are properly installed and display their version:\/\/ Display the JDK version javac -version<\/strong> javac 13.0.1 \/\/ Display the JRE version java -version<\/strong> java version “13.0.1” 2019-10-15 Java(TM) SE Runtime Environment (build 13.0.1+9) Java HotSpot(TM) 64-Bit Server VM (build 13.0.1+9, mixed mode, sharing)<\/li><\/ol>\n\n\n\n
          Step 5: Write a Hello-World Java Program<\/h5>\n\n\n\n
          1. Create a directory to keep your works, e.g., “d:\\myProject<\/code>” or “c:\\myProject<\/code>“. Do NOT save your works in “Desktop” or “Documents” as they are hard to locate. The directory name shall not contain blank<\/em> or special characters. Use meaningful but short name as it is easier to type.<\/li>
          2. Launch a programming text editor (such as TextPad<\/a>, NotePad++<\/a>, Sublime Text, Atom). Begin with a new file<\/em> and enter the following source code. Save the file as “Hello.java<\/code>“, under your work directory (e.g., d:\\myProject<\/code>).\/* * First Java program to say Hello *\/ public class Hello { \/\/ Save as “Hello.java” under “d:\\myProject” public static void main(String[] args) { System.out.println(“Hello, world!”); } }<\/li><\/ol>\n\n\n\n
            Step 6: Compile and Run the Hello-World Java Program<\/h5>\n\n\n\n
            \"JavaBasics_GettingStarted.png\"<\/figure>\n\n\n\n

            To compile the source code “Hello.java<\/code>“:<\/p>\n\n\n\n

            1. Start a CMD Shell (Search \u21d2 enter “cmd” \u21d2 select “Command Prompt”).<\/li>
            2. Set the Current Drive<\/em> to the drive where you saved your source file “Hello.java<\/code>“.
              If you use drive “c”, skip this step.
              Else if you use drive “d<\/code>“, enter “d:<\/strong><\/code>” as follow:d:<\/strong> D:\\xxx><\/li>
            3. Set the Current Working Directory<\/em> to the directory that you saved your source file via the cd<\/code><\/strong> (Change Directory<\/em>) command. For example, suppose that your source file is saved in directory “myProject<\/code>“.
              cd \\myProject<\/strong> D:\\myProject><\/li>
            4. Issue a dir<\/code><\/strong> (List Directory<\/em>) command to confirm that your source file is present in the current directory<\/em>.dir<\/strong> …… xx-xxx-xx xx:xx PM 277 Hello.java<\/strong> ……<\/li>
            5. Invoke the JDK compiler “javac<\/code><\/strong>” to compile the source code “Hello.java<\/code>“.javac Hello.java<\/strong> \/\/ If error message appears, correct your source code and re-compileThe compilation is successful if the command prompt returns. Otherwise, error messages would be shown. Correct the errors in your source file and re-compile. Check “Common JDK Installation Errors<\/a>“, if you encounter problem compiling your program.<\/li>
            6. The output of the compilation is a Java class called “Hello.class<\/code>“. Issue a dir<\/code><\/strong> (List Directory<\/em>) command again to check for the output.dir<\/strong> …… xx-xxx-xx xx:xx PM 416 Hello.class<\/strong> xx-xxx-xx xx:xx PM 277 Hello.java ……<\/li><\/ol>\n\n\n\n

              To run the program, invoke the Java Runtime “java<\/strong><\/code>“:<\/p>\n\n\n\n

              java Hello<\/strong>\nHello, world!<\/pre>\n\n\n\n
              Everything that can possibly go wrong will go wrong<\/strong>: Read “JDK Installation Common Errors<\/a>“.<\/p>\n\n\n\n
              Step 7: (For Advanced Users Only) JDK’s Source Code<\/h5>\n\n\n\n
              Source code for JDK is provided and kept in “<JAVA_HOME>\\lib\\src.zip<\/code>” (or “<JAVA_HOME>\\src.zip<\/code>” prior to JDK 9). I strongly recommend that you to go through some of the source files such as “String.java<\/code>“, “Math.java<\/code>“, and “Integer.java<\/code>“, under “java\\lang<\/code>“, to learn how experts program.<\/p>\n","protected":false},"excerpt":{"rendered":"
              1.  How To Install JDK on Windows Step 0: Un-Install Older Version(s) of JDK\/JRE I recommend that you install only the latest JDK. Although you can install multiple versions of JDK\/JRE concurrently, it is messy. If you have previously installed older version(s) of JDK\/JRE, un-install ALL of them. Goto “Control Panel” \u21d2 (optional) “Programs” \u21d2 “Programs and Features” […]<\/p>\n","protected":false},"author":1,"featured_media":183,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[],"class_list":["post-181","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java"],"_links":{"self":[{"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/posts\/181","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/comments?post=181"}],"version-history":[{"count":1,"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/posts\/181\/revisions"}],"predecessor-version":[{"id":184,"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/posts\/181\/revisions\/184"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/media\/183"}],"wp:attachment":[{"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/media?parent=181"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/categories?post=181"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/bhtinstitute.com\/knowhow\/wp-json\/wp\/v2\/tags?post=181"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}