JDK 8 tools.jar is the JAR file for JDK 8 tools. It contains Java classes to support different JDK tool commands:

sun.applet.Main - Supports the "appletviewer" command.
sun.rmi.rmic.Main - Supports the "rmic" command.
sun.security.tools.jarsigner.Main - Supports the "jarsigner" command.
sun.tools.jar.Main - Supports the "jar" command.
sun.tools.javac.Main - Supports the "javac" command. 
sun.tools.jcmd.JCmd - Supports the "jcmd" command.
sun.tools.jinfo.JInfo - Supports the "jinfo" command.
sun.tools.jmap.JMap - Supports the "jmap" command.
sun.tools.jps.Jps - Supports the "jps" command.
sun.tools.jstack.JStack - Supports the "jstack" command.
sun.tools.jstat.Jstat - Supports the "jstat" command.
sun.tools.jstatd.Jstatd - Supports the "jstatd" command.
sun.tools.native2ascii.Main - Supports the "native2ascii" command.
sun.tools.serialver.SerialVer - Supports the "serialver" command.
... 

JAR File Information:

Directory of C:\fyicenter\jdk-1.8.0_191\lib
      18,256,125 tools.jar

Package Content:

<<<Previous part
sun/tools/util/CommandLine.class
sun/tools/util/ModifierFilter.class

⇒ JRE 8 charsets.jar - Character Set Encoding

⇐ JDK 8 sa-jdi.jar - HSDB (Hotspot Debugger)

⇑ Download and Use JDK 8

⇑⇑ FAQ for JDK (Java Development Kit)