The Java Development Kit (JDK) purpose is to develop Java applications. The Java Runtime Environment (JRE) purpose is to run Java applications. Executing an ‘ls -Al /usr/bin/* | grep -e java -e jar -e appletviewer -e mozilla-javaplugin.so’ command, we see that each Java executable is actually a symbolic link to the alternatives directory, not a binary executable file.įind Your Processor’s Architecture JRE or JDK? This directory contains the majority of binary executables on the system. We can see this system at work by changing to our ‘/usr/bin’ directory. Instead, it is a symbolic link to a name in the alternatives directory, which in turn is a symbolic link to the actual file referenced.’ The alternatives system and the system administrator together determine which actual file is referenced by this generic name. The generic name is not a direct symbolic link to the selected alternative. AlternativesĪccording to, alternatives ‘make it possible for several programs fulfilling the same or similar functions to be installed on a single system at the same time. A generic name in the filesystem is shared by all files providing interchangeable functionality.
In a many software development environments, you may need different versions of Java, depending on different client project’s level of technology. By selecting an alternative version of Java, we control which java.exe binary executable file the system calls when the ‘java’ command is executed. These three versions are referred to as ‘alternatives’, thus the ‘alternatives’ command. There are two other Java versions also installed but not active, an Oracle 1.7.0_17 JRE version and an older 1.7.0_04 JDK version. That version is located in the ‘/usr/lib/jvm/jdk1.7.0_17’ subdirectory. In the above example, the 1.7.0_17 JDK version of Java is configured and active.
0 kommentar(er)
