Remove unnecessary method in JvmOptionsParser (#52173)

Back when the distribution launchers were compiled to target JDK 7, we
did not have access to the String#join method to space-delimit JVM
options. Since the launchers now target the same minimum JDK as
Elasticsearch itself, we now have access to this method and can replace
the use of spaceDelimitJvmOptions with String#join. This commit does
that.

distribution/tools/launchers/src/main/java/org/elasticsearch/tools/launchers/JvmOptionsParser.java

@@ -35,7 +35,6 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -95,8 +94,7 @@ public static void main(final String[] args) throws InterruptedException, IOExce
 
         try {
             final List<String> jvmOptions = parser.jvmOptions(Paths.get(args[0]), System.getenv("ES_JAVA_OPTS"), substitutions);
-            final String spaceDelimitedJvmOptions = spaceDelimitJvmOptions(jvmOptions);
-            Launchers.outPrintln(spaceDelimitedJvmOptions);
+            Launchers.outPrintln(String.join(" ", jvmOptions));
         } catch (final JvmOptionsFileParserException e) {
             final String errorMessage = String.format(
                 Locale.ROOT,
@@ -340,22 +338,4 @@ static void parse(
         }
     }
 
-    /**
-     * Delimits the specified JVM options by spaces.
-     *
-     * @param jvmOptions the JVM options
-     * @return a single-line string containing the specified JVM options in the order they appear delimited by spaces
-     */
-    static String spaceDelimitJvmOptions(final List<String> jvmOptions) {
-        final StringBuilder spaceDelimitedJvmOptionsBuilder = new StringBuilder();
-        final Iterator<String> it = jvmOptions.iterator();
-        while (it.hasNext()) {
-            spaceDelimitedJvmOptionsBuilder.append(it.next());
-            if (it.hasNext()) {
-                spaceDelimitedJvmOptionsBuilder.append(" ");
-            }
-        }
-        return spaceDelimitedJvmOptionsBuilder.toString();
-    }
-
 }

distribution/tools/launchers/src/test/java/org/elasticsearch/tools/launchers/JvmOptionsParserTests.java

@@ -246,13 +246,4 @@ public void accept(final int lineNumber, final String line) {
         assertThat(seenInvalidLines, equalTo(invalidLines));
     }
 
-    public void testSpaceDelimitedJvmOptions() {
-        assertThat(JvmOptionsParser.spaceDelimitJvmOptions(Collections.singletonList("-Xms1g")), equalTo("-Xms1g"));
-        assertThat(JvmOptionsParser.spaceDelimitJvmOptions(Arrays.asList("-Xms1g", "-Xmx1g")), equalTo("-Xms1g -Xmx1g"));
-        assertThat(
-            JvmOptionsParser.spaceDelimitJvmOptions(Arrays.asList("-Xms1g", "-Xmx1g", "-XX:+UseG1GC")),
-            equalTo("-Xms1g -Xmx1g -XX:+UseG1GC")
-        );
-    }
-
 }