RFR: JMC-6266: JDK 8 specific code in core (String.join)

[Marcus Hirt]

Hi all,

Please review this fix for getting rid of some JDK 8-specific code that has
snuck into core.

Jira:  https://bugs.openjdk.java.net/browse/JMC-6266
Patch:

<---8<--->
diff -r abb4b7f54009
core/org.openjdk.jmc.flightrecorder.rules.jdk/src/main/java/org/openjdk/jmc/
flightrecorder/rules/jdk/general/DuplicateFlagsRule.java
---
a/core/org.openjdk.jmc.flightrecorder.rules.jdk/src/main/java/org/openjdk/jm
c/flightrecorder/rules/jdk/general/DuplicateFlagsRule.java     Thu Dec 06
19:12:44 2018 +0100
+++
b/core/org.openjdk.jmc.flightrecorder.rules.jdk/src/main/java/org/openjdk/jm
c/flightrecorder/rules/jdk/general/DuplicateFlagsRule.java     Tue Dec 11
13:47:26 2018 +0100
@@ -44,6 +44,7 @@
 import org.openjdk.jmc.common.item.Aggregators;
 import org.openjdk.jmc.common.item.IItemCollection;
 import org.openjdk.jmc.common.util.IPreferenceValueProvider;
+import org.openjdk.jmc.common.util.StringToolkit;
 import org.openjdk.jmc.common.util.TypedPreference;
 import org.openjdk.jmc.flightrecorder.jdk.JdkAttributes;
 import org.openjdk.jmc.flightrecorder.jdk.JdkFilters;
@@ -81,7 +82,7 @@
                                StringBuilder sb = new StringBuilder();
                                sb.append("<ul>"); //$NON-NLS-1$
                                for (ArrayList<String> dupe : dupes) {
-                                    sb.append("<li>" +
Encode.forHtml(String.join(", ", dupe)) + "</li>"); //$NON-NLS-1$
//$NON-NLS-2$
+                                    sb.append("<li>" +
Encode.forHtml(StringToolkit.join(dupe, ", ")) + "</li>"); //$NON-NLS-1$
//$NON-NLS-2$
                                }
                                sb.append("</ul>"); //$NON-NLS-1$
                                String shortDescription = dupes.size() > 1
<---8<--->

Kind regards,
Marcus