Revert "Fix support for .jar binaries, fixes #10426"

This reverts commit fa65804c99.

src/Composer/Installer/BinaryInstaller.php

@@ -158,10 +158,6 @@ class BinaryInstaller
             return trim($match[1]);
         }
 
-        if (substr($bin, -4) === '.jar') {
-            return 'java -jar ';
-        }
-
         return 'php';
     }
 
@@ -228,7 +224,7 @@ class BinaryInstaller
         $binPath = $this->filesystem->findShortestPath($link, $bin);
         $caller = self::determineBinaryCaller($bin);
 
-        // if the target is a php file, we run the unixy proxy file (a php script in this case)
+        // if the target is a php file, we run the unixy proxy file
         // to ensure that _composer_autoload_path gets defined, instead
         // of running the binary directly
         if ($caller === 'php') {
@@ -398,11 +394,6 @@ include $binPathExported;
 PROXY;
         }
 
-        $caller = '';
-        if (substr($bin, -4) === '.jar') {
-            $caller = 'java -jar ';
-        }
-
         return <<<PROXY
 #!/usr/bin/env sh
 
@@ -424,7 +415,7 @@ fi
 
 export COMPOSER_BIN_DIR=\$(cd "\${self%[/\\\\]*}" > /dev/null; pwd)
 
-$caller"\${dir}/$binFile" "\$@"
+"\${dir}/$binFile" "\$@"
 
 PROXY;
     }