C:\Users\gtgam>cd music

C:\Users\gtgam\Music>dir
 Volume in drive C is OS
 Volume Serial Number is 9058-DE25

 Directory of C:\Users\gtgam\Music

05/29/2019  12:54 PM    <DIR>          .
05/29/2019  12:54 PM    <DIR>          ..
05/29/2019  12:18 PM         4,888,981 forge-1.12.2-14.23.5.2768-universal.jar
05/29/2019  12:18 PM        30,222,121 minecraft_server.1.12.2.jar
05/29/2019  12:54 PM    <DIR>          New folder (2)
               2 File(s)     35,111,102 bytes
               3 Dir(s)  755,158,241,280 bytes free

C:\Users\gtgam\Music>forge-1.12.2-14.23.5.2768-universal.jar

C:\Users\gtgam\Music>dir
 Volume in drive C is OS
 Volume Serial Number is 9058-DE25

 Directory of C:\Users\gtgam\Music

05/29/2019  12:54 PM    <DIR>          .
05/29/2019  12:54 PM    <DIR>          ..
05/29/2019  12:18 PM         4,888,981 forge-1.12.2-14.23.5.2768-universal.jar
05/29/2019  12:18 PM        30,222,121 minecraft_server.1.12.2.jar
05/29/2019  12:54 PM    <DIR>          New folder (2)
               2 File(s)     35,111,102 bytes
               3 Dir(s)  755,005,313,024 bytes free

C:\Users\gtgam\Music>java
Usage: java [-options] class [args...]
           (to execute a class)
   or  java [-options] -jar jarfile [args...]
           (to execute a jar file)
where options include:
    -d32          use a 32-bit data model if available
    -d64          use a 64-bit data model if available
    -server       to select the "server" VM
                  The default VM is server.

    -cp <class search path of directories and zip/jar files>
    -classpath <class search path of directories and zip/jar files>
                  A ; separated list of directories, JAR archives,
                  and ZIP archives to search for class files.
    -D<name>=<value>
                  set a system property
    -verbose:[class|gc|jni]
                  enable verbose output
    -version      print product version and exit
    -version:<value>
                  Warning: this feature is deprecated and will be removed
                  in a future release.
                  require the specified version to run
    -showversion  print product version and continue
    -jre-restrict-search | -no-jre-restrict-search
                  Warning: this feature is deprecated and will be removed
                  in a future release.
                  include/exclude user private JREs in the version search
    -? -help      print this help message
    -X            print help on non-standard options
    -ea[:<packagename>...|:<classname>]
    -enableassertions[:<packagename>...|:<classname>]
                  enable assertions with specified granularity
    -da[:<packagename>...|:<classname>]
    -disableassertions[:<packagename>...|:<classname>]
                  disable assertions with specified granularity
    -esa | -enablesystemassertions
                  enable system assertions
    -dsa | -disablesystemassertions
                  disable system assertions
    -agentlib:<libname>[=<options>]
                  load native agent library <libname>, e.g. -agentlib:hprof
                  see also, -agentlib:jdwp=help and -agentlib:hprof=help
    -agentpath:<pathname>[=<options>]
                  load native agent library by full pathname
    -javaagent:<jarpath>[=<options>]
                  load Java programming language agent, see java.lang.instrument
    -splash:<imagepath>
                  show splash screen with specified image
See http://www.oracle.com/technetwork/java/javase/documentation/index.html for more details.

C:\Users\gtgam\Music>dir
 Volume in drive C is OS
 Volume Serial Number is 9058-DE25

 Directory of C:\Users\gtgam\Music

05/29/2019  12:54 PM    <DIR>          .
05/29/2019  12:54 PM    <DIR>          ..
05/29/2019  12:18 PM         4,888,981 forge-1.12.2-14.23.5.2768-universal.jar
05/29/2019  12:18 PM        30,222,121 minecraft_server.1.12.2.jar
05/29/2019  12:54 PM    <DIR>          New folder (2)
               2 File(s)     35,111,102 bytes
               3 Dir(s)  755,005,304,832 bytes free

C:\Users\gtgam\Music>jav -jar forge-1.12.2-14.23.5.2768-universal.jar
'jav' is not recognized as an internal or external command,
operable program or batch file.

C:\Users\gtgam\Music>dir
 Volume in drive C is OS
 Volume Serial Number is 9058-DE25

 Directory of C:\Users\gtgam\Music

05/29/2019  12:54 PM    <DIR>          .
05/29/2019  12:54 PM    <DIR>          ..
05/29/2019  12:18 PM         4,888,981 forge-1.12.2-14.23.5.2768-universal.jar
05/29/2019  12:18 PM        30,222,121 minecraft_server.1.12.2.jar
05/29/2019  12:54 PM    <DIR>          New folder (2)
               2 File(s)     35,111,102 bytes
               3 Dir(s)  755,005,304,832 bytes free

C:\Users\gtgam\Music>java jar- forge-1.12.2-14.23.5.2768-universal.jar
Error: Could not find or load main class jar-

C:\Users\gtgam\Music>java jar-forge-1.12.2-14.23.5.2768-universal.jar
Error: Could not find or load main class jar-forge-1.12.2-14.23.5.2768-universal.jar

C:\Users\gtgam\Music>java jar- forge-1.12.2-14.23.5.2768-universal.jar
Error: Could not find or load main class jar-

C:\Users\gtgam\Music>java jar-forge-1.12.2-14.23.5.2768-universal.jar
Error: Could not find or load main class jar-forge-1.12.2-14.23.5.2768-universal.jar