Java Development Kit 64-bit 8 Update 91: Features and Benefits
Java 8 91 Download: What You Need to Know
Java is one of the most popular and widely used programming languages in the world. It is used to create applications and applets that run on various platforms, such as Windows, Linux, Mac OS, Android, and more. Java is also known for its reliability, security, performance, and compatibility.
Java 8 91 Download
If you are a developer, a student, or a user who wants to run Java programs on your computer, you need to download and install the Java Development Kit (JDK) and the Java Runtime Environment (JRE). These are the essential components that allow you to compile, debug, run, and execute Java programs.
However, not all versions of Java are the same. There are different updates and releases that offer different features, improvements, bug fixes, and security patches. One of the latest versions of Java is Java 8 91, which was released in April 2021. In this article, we will tell you everything you need to know about Java 8 91, including what it is, how to download it, how to use it, and more.
What is Java 8 91?
The features and benefits of Java 8 91
Java SE Development Kit (JDK) 8 Update 91 (also known as JDK 8u91) is a patch-set update that includes security fixes and performance improvements. It also includes some new features and changes, such as:
A new system property called jdk.serialFilter that allows you to specify a filter for incoming serialization data. This can help you prevent deserialization attacks by blocking unwanted or malicious data.
A new security property called jdk.tls.ephemeralDHKeySize that allows you to specify the minimum key size for ephemeral Diffie-Hellman keys used in TLS connections. This can help you enhance the security of your TLS communications by using stronger keys.
A new tool called jdeps that allows you to analyze the dependencies of your Java classes and JAR files. This can help you optimize your code by removing unused or redundant dependencies.
A new option called -XX:+UseSHA that allows you to enable the use of SHA-1 and SHA-2 algorithms for intrinsics. This can help you improve the performance of your cryptographic operations by using hardware acceleration.
The differences between Java SE Development Kit (JDK) Update Release Version Numbering Scheme
Java SE Development Kit (JDK) Update Release Version Numbering Scheme
major release of Java SE. For example, 8 is the major version number of Java SE 8.
JDK Minor Version NumberThe minor version number identifies the minor update of Java SE. For example, 0 is the minor version number of Java SE 8.0.
JDK Update Release NumberThe update release number identifies the update release of Java SE. For example, 91 is the update release number of Java SE 8u91.
JDK Patch Release NumberThe patch release number identifies the patch release of Java SE. For example, 15 is the patch release number of Java SE 8u91-b15.
JDK Build NumberThe build number identifies the specific build of Java SE. For example, b15 is the build number of Java SE 8u91-b15.
As you can see, Java 8 91 is the 91st update release of Java SE 8, which has a major version number of 8, a minor version number of 0, and a patch release number of 0. The build number may vary depending on the platform and the source of download.
How to download Java 8 91?
If you want to download and install Java 8 91 on your computer, you need to follow these steps:
The official sources and links for Java 8 91
The official source for downloading Java 8 91 is the Oracle website, which provides different links for different platforms and purposes. Here are some of the links you can use:
If you want to download JDK 8u91 for Windows, Linux, Mac OS X, or Solaris, you can use this link: https://www.oracle.com/java/technologies/javase/javase-jdk8-downloads.html
If you want to download JRE 8u91 for Windows, Linux, Mac OS X, or Solaris, you can use this link: https://www.oracle.com/java/technologies/javase-jre8-downloads.html
If you want to download JDK or JRE 8u91 for other platforms or architectures, you can use this link: https://www.oracle.com/java/technologies/javase-downloads.html
If you want to download JDK or JRE 8u91 for embedded devices, you can use this link: https://www.oracle.com/java/technologies/javase-embedded-downloads.html
If you want to download JDK or JRE 8u91 for servers or cloud deployments, you can use this link: https://www.oracle.com/java/technologies/server-jre-downloads.html
Before you download Java 8 91 from any of these links, you need to accept the Oracle Binary Code License Agreement for Java SE, which is a legal agreement that governs your use of Java SE. You can read the agreement here: https://www.oracle.com/downloads/licenses/binary-code-license.html
The system requirements and compatibility for Java 8 91
Before you install Java 8 91 on your computer, you need to make sure that your system meets the minimum requirements and is compatible with Java SE. Here are some of the requirements and compatibility factors you need to consider:
The operating system: You need to have a supported operating system that can run Java SE. For example, Windows Vista SP2 or later, Linux kernel 2.6.18 or later, Mac OS X 10.8.3 or later, or Solaris SPARC or x64.
The processor: You need to have a supported processor that can run Java SE. For example, Intel Pentium II or later, AMD Athlon or later, ARMv7 or later, or SPARC T4 or later.
The memory: You need to have enough memory to run Java SE and your applications. For example, at least 128 MB of RAM for JRE and at least 256 MB of RAM for JDK.
for JRE and at least 250 MB of disk space for JDK.
The browser: You need to have a supported browser that can run Java applets and web start applications. For example, Internet Explorer 9 or later, Firefox 38 or later, Chrome 45 or later, or Safari 8 or later.
The firewall: You need to have a configured firewall that can allow Java SE to access the internet and communicate with other applications. For example, you may need to open some ports or add some exceptions for Java SE.
You can check the detailed system requirements and compatibility for Java SE 8 here: https://www.oracle.com/java/technologies/javase/products-doc-jdk8-jre8-certconfig.html
The installation and configuration steps for Java 8 91
After you download Java 8 91 from the official source, you need to install and configure it on your computer. The installation and configuration steps may vary depending on your platform and your preferences, but here are some general steps you can follow:
Run the downloaded file (such as jdk-8u91-windows-x64.exe or jre-8u91-macosx-x64.dmg) and follow the instructions on the screen. You may need to accept the license agreement, choose the installation directory, and select the components you want to install.
After the installation is complete, you may need to set some environment variables to make Java SE accessible and usable. For example, you may need to set JAVA_HOME to point to the installation directory of JDK, and PATH to include the bin directory of JDK or JRE.
You may also need to verify that Java SE is installed and working correctly. For example, you can open a command prompt or a terminal and type java -version or javac -version to check the version of JRE or JDK. You can also type jjs or jdeps to test some of the new features of Java 8 91.
If you want to run Java applets or web start applications in your browser, you may need to enable Java SE in your browser settings. For example, you can go to the browser's advanced settings and look for the option to enable or disable Java SE.
If you want to use some of the new security properties or options of Java 8 91, you may need to edit the java.security file in the lib/security directory of JDK or JRE. For example, you can add or modify the values of jdk.serialFilter or jdk.tls.ephemeralDHKeySize.
You can find more detailed installation and configuration instructions for Java SE 8 here: https://docs.oracle.com/javase/8/docs/technotes/guides/install/install_overview.html
How to use Java 8 91?
Once you have installed and configured Java 8 91 on your computer, you can start using it to create and run Java programs. Here are some of the basic commands and tools you can use:
The basic commands and tools for Java 8 91
The basic commands and tools for Java SE are located in the bin directory of JDK or JRE. Here are some of the most common ones:
java: This command launches the Java application launcher, which executes a Java class or a JAR file. For example, java HelloWorld runs the HelloWorld class, and java -jar myapp.jar runs the myapp JAR file.
javac: This command launches the Java compiler, which compiles a Java source file into a bytecode class file. For example, javac HelloWorld.java compiles the HelloWorld.java file into HelloWorld.class file.
javadoc: This command launches the Java documentation generator, which creates HTML documentation from Java source files. For example, javadoc -d docs HelloWorld.java creates HTML documentation for HelloWorld.java in the docs directory.
jdeps: This command launches the Java class dependency analyzer, which analyzes the dependencies of Java classes and JAR files. For example, jdeps -verbose HelloWorld.class shows the verbose dependency information for HelloWorld.class file, and jdeps -jdkinternals myapp.jar shows the JDK internal API dependencies for myapp JAR file.
jar: This command launches the Java archive tool, which creates and manipulates JAR files. For example, jar cvf myapp.jar *.class creates a JAR file named myapp.jar from all the class files in the current directory, and jar xvf myapp.jar extracts all the files from myapp JAR file.
jarsigner: This command launches the Java archive signer, which signs and verifies JAR files. For example, jarsigner -keystore mykeystore myapp.jar myalias signs the myapp JAR file with the private key associated with myalias in the mykeystore keystore, and jarsigner -verify -verbose -certs myapp.jar verifies the signature and certificate information of myapp JAR file.
keytool: This command launches the key and certificate management tool, which manages keystores, keys, certificates, and truststores. For example, keytool -genkeypair -alias myalias -keystore mykeystore generates a key pair and a self-signed certificate with the alias myalias in the keystore named mykeystore, and keytool -list -v -keystore mykeystore lists the verbose information of all the entries in the mykeystore keystore.
jconsole: This command launches the Java monitoring and management console, which provides a graphical interface for monitoring and managing Java applications. For example, jconsole connects to a local Java application and displays its memory usage, threads, classes, CPU usage, and more.
jvisualvm: This command launches the Java visual VM tool, which provides a graphical interface for profiling and troubleshooting Java applications. For example, jvisualvm connects to a local or remote Java application and displays its heap dump, thread dump, CPU sampling, memory sampling, and more.
You can find more information about these and other commands and tools for Java SE 8 here: https://docs.oracle.com/javase/8/docs/technotes/tools/index.html
The common errors and troubleshooting tips for Java 8 91
While using Java 8 91, you may encounter some common errors or issues that can affect your Java programs or applications. Here are some of the common errors and troubleshooting tips for Java 8 91:
If you get an error message like Error: Could not create the Java Virtual Machine or Error: A fatal exception has occurred. Program will exit, it means that there is a problem with creating or running the Java virtual machine (JVM). This could be caused by various factors, such as insufficient memory, incorrect or incompatible JVM options, corrupted or missing JVM files, or incompatible hardware or software. To fix this error, you can try some of these solutions:
Check your memory usage and availability and make sure you have enough free memory to run your Java program or application.
Check your JVM options and make sure they are valid and compatible with your JVM version and platform. For example, you can use -Xmx to specify the maximum heap size for your JVM.
Check your JVM files and make sure they are not corrupted or missing. You can reinstall or update your JDK or JRE to get the latest JVM files.
Check your hardware or software compatibility and make sure they are not conflicting with your JVM. You can update your drivers or software to get the latest versions.
If you get an error message like Error: Could not find or load main class HelloWorld, it means that there is a problem with finding or loading your main class. This could be caused by various factors, such as incorrect or missing class name, classpath, package name, file name, or file extension. To fix this error, you can try some of these solutions:
your file name should be HelloWorld.java and your file extension should be .java.
Check your classpath and make sure it includes the directory or the JAR file where your main class is located. For example, you can use -cp or -classpath to specify the classpath for your JVM.
Check your package name and make sure it matches with your directory structure. For example, if your package name is com.example, your main class should be in the com/example directory.
Check your spelling and case sensitivity and make sure they are consistent with your main class. For example, HelloWorld is not the same as Helloworld or helloWorld.
If you get an error message like Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorld, it means that there is a problem with loading a dependent class. This could be caused by various factors, such as missing or incompatible JAR files, classpath issues, or class version mismatch. To fix this error, you can try some of these solutions:
Check your JAR files and make sure they are present and compatible with your main class. For example, if your main class depends on a third-party library, you need to have the corresponding JAR file in your classpath or in the same directory as your main class.
Check your classpath and make sure it includes all the directories and JAR files that contain your dependent classes. For example, you can use -cp or -classpath to specify the classpath for your JVM.
Check your class version and make sure it matches with the JVM version. For example, if your class was compiled with JDK 8, you need to run it with JRE 8 or later.
You can find more information about these and other errors and troubleshooting tips for Java SE 8 here: https://docs.oracle.com/javase/8/docs/technotes/guides/troubleshoot/index.html
The best practices and tips for Java 8 91
To use Java 8 91 effectively and efficiently, you can follow some of the best practices and tips for Java SE 8. Here are some of them:
Keep your Java SE updated and secure. For example, download and install the latest updates and patches from the official source, enable automatic updates if possible, check the security alerts and advisories from Oracle, use strong encryption algorithms and keys for TLS connections, use serialization filters to prevent deserialization attacks, and more.
Optimize your Java SE performance and memory usage. For example, use appropriate JVM options and tuning parameters, use SHA intrinsics for cryptographic operations, use jdeps tool to analyze and remove unused dependencies, use jvisualvm tool to profile and troubleshoot your Java applications, use garbage collection algorithms and settings that suit your application needs, and more.
imports, and comments, use proper indentation and spacing for your code blocks, use meaningful and descriptive names for your identifiers, use comments and javadoc to document your code, use modular and reusable code design, and more.
Test and debug your Java SE code and applications. For example, use unit testing frameworks and tools to verify your code functionality and quality, use debugging tools and techniques to identify and fix your code errors and exceptions, use logging and tracing tools to monitor and record your code behavior and performance, use code analysis and review tools to check and improve your code style and structure, and more.
You can find more information about these and other best practices and tips for Java SE 8 here: https://docs.oracle.com/javase/8/docs/index.html
In this article, we have covered everything you need to know about Java 8 91, including what it is, how to download it, how to use it, and more. We hope that this article has helped you understand and appreciate the features and benefits of Java 8 91, as well as the challenges and solutions of using it. We also hope that this article has inspired you to explore and learn more about Java SE 8 and its updates.
If you have any questions or feedback about this article or Java 8 91, please feel free to contact us or leave a comment below. We would love to hear from you and help you with your Java SE needs. Thank