chore: revert to Java 8 syntax

I didn't realise we were still using Java 8 to build the
connector. Given that it has been deprecated in Kafka since v3.0
this doesn't seem like the right choice, but that feels like too
significant a change to include in this pull request, so for now
I'll just remove the newer syntax I'd used.

Signed-off-by: Dale Lane <[email protected]>

Author: dalelane

src/main/java/com/ibm/eventstreams/connect/mqsource/MQSourceConnector.java

@@ -19,6 +19,7 @@
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -776,8 +777,11 @@ public void ensureValid(final String name, final Object value) {
                 final JsonDeserializer deserializer = new JsonDeserializer();
                 final JsonConverter conv = new JsonConverter()
             ) {
+                final Map<String, String> converterConfig = new HashMap<>();
+                converterConfig.put(JsonConverterConfig.TYPE_CONFIG, ConverterType.VALUE.getName());
+                conv.configure(converterConfig);
+
                 final JsonNode jsonStr = deserializer.deserialize(trimmedStr, trimmedStr.getBytes());
-                conv.configure(Map.of(JsonConverterConfig.TYPE_CONFIG, ConverterType.VALUE.getName()));
                 conv.asConnectSchema(jsonStr);
             } catch (final DataException exc) {
                 throw new ConfigException(name, value, exc.getMessage());

src/test/java/com/ibm/eventstreams/connect/mqsource/builders/RecordBuilderFactoryTest.java

@@ -16,6 +16,7 @@
 package com.ibm.eventstreams.connect.mqsource.builders;
 
 import org.assertj.core.api.Assertions;
+import org.junit.Before;
 import org.junit.Test;
 
 import com.ibm.eventstreams.connect.mqsource.MQSourceConnector;
@@ -25,11 +26,14 @@
 
 public class RecordBuilderFactoryTest {
 
-    final Map<String, String> placeholderProps = Map.of(
-        "mq.queue.manager", "placeholder",
-        "mq.queue", "placeholder",
-        "topic", "placeholder"
-    );
+    final Map<String, String> placeholderProps = new HashMap<>();
+
+    @Before
+    public void prepareProperties() {
+        placeholderProps.put("mq.queue.manager", "placeholder");
+        placeholderProps.put("mq.queue", "placeholder");
+        placeholderProps.put("topic", "placeholder");
+    }
 
     @Test
     public void testGetRecordBuilder_ForJsonRecordBuilder() {