Linux Ubuntu - OpenJdk Java 13 Install Setup

To uninstall OpenJDK

> sudo apt-get autoremove openjdk*

> sudo apt-get purge openjdk*

Install > 1.9 JDK 1.3

> sudo apt install -y curl

> curl -O https://download.java.net/java/GA/jdk13/5b8a42f3905b406298b72d750b6919f6/33/GPL/openjdk-13_linux-x64_bin.tar.gz

> tar xvf openjdk-13_linux-x64_bin.tar.gz

> sudo mv jdk-13 /usr/java/

> sudo nano /etc/profile
     # Go to after fi end and paste the below lines
    JAVA_HOME=/usr/java/jdk-13.0.2
    PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
    export JAVA_HOME
    export JRE_HOME
    export PATH


# Configure Java Alternatives
> sudo update-alternatives --install "/usr/bin/java" "java" "/usr/java/jdk-13.0.2/bin/java" 1

# Configure Javac Alternatives
> sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/java/jdk-13.0.2/bin/javac" 1

# Check version
> java -version

# Use only in case of multiple JDKs installed

# Configure Java
> sudo update-alternatives --config java

# Configure Java Compiler
> sudo update-alternatives --config javac

>javac -version

>java version

JDK Difference 1.8 vs 1.7 vs 1.6 .... 1.1

Java 8 (a.k.a 1.8) JSR 337, what's new Language changes: lambda expressions (JSR 335, includes method handles) continuation of Project Coin (small language improvements) annotations on Java types Library changes: Improved Date and Time API	Java 7 (a.k.a 1.7) JSR 336, features and enhancements Language changes: Project Coin (small changes) switch on Strings try-with-resources diamond operator Library changes: new abstracted file-system API (NIO.2) (with support for virtual filesystems) improved concurrency libraries elliptic curve encryption more incremental upgrades Platform changes: support for dynamic languages
Java 6 (a.k.a 1.6) JSR 270. features and enhancements Mostly incremental improvements to existing libraries, no new language features (except for the @Override snafu).	Java 5 (a.k.a 1.5) JSR 176, features and enhancements Language Changes: generics (that's the big one) annotations enum types varargs, enhanced for loops (for-each) Library changes: concurrency utilities in java.util.concurrent
Java 1.4 JSR 59 Language changes: the assert keyword Library changes: regular expressions support NIO integrated XML handling	Java 1.3 Mostly minor improvements, really. Platform changes: HotSpot JVM: improvement over the original JIT
Java 1.2 Language changes: the strictfp keyword Library changes: a unified collections system Swing as a new UI-System on top of AWT Platform changes a real JIT, greatly improving speed	Java 1.1 Language changes: inner classes Library changes: AWT event changes JDBC, RMI reflection
Java 1.0 Initial release, everything is new ;-)

Java File content detector - Apache Tika

1. renamed sample.txt to sample.pdf

2. Add tika-core-1.11.jar in your lib

3. java class
    Output : text/plain File is of type - .txt


import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.tika.config.TikaConfig;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.mime.MimeType;
import org.apache.tika.mime.MimeTypeException;

public class TikaExample
{

    public static void main ( String [] args ) throws IOException, MimeTypeException
    {

      TikaConfig config = TikaConfig.getDefaultConfig ();

        // renamed sample.txt to sample.pdf
        File file = new File ( "D:/drvijay/Reliance/testing/sample.exe" );
        InputStream stream = new FileInputStream ( file );
        // whatever the source you get inputstream, please add buffer for mark/reset support,
        // else u may get exception
        InputStream bufferedIn = new BufferedInputStream ( stream );

        final Metadata metadata = new Metadata ();
        metadata.set ( Metadata.RESOURCE_NAME_KEY, file.getName () );
        MediaType mediaType = config.getMimeRepository ().detect ( bufferedIn, metadata );
        // MediaType mediaType = config.getMimeRepository ().detect ( bufferedIn, new Metadata() );
        MimeType mimeType = config.getMimeRepository ().forName ( mediaType.toString () );
        String extension = mimeType.getExtension ();

        System.out.println ( mimeType + " File is of type - " + extension );
    }
}

linux Ubuntu JDK Java Setup Installation

java 1.8
*******

Type the below commands.

    Installing Java 8
        $ sudo add-apt-repository ppa:webupd8team/java
        $ sudo apt-get update
        $ sudo apt-get install oracle-java8-installer
    Verify java
        $ java -version
    Configuring Java Environment
        $ sudo apt-get install oracle-java8-set-default