Remove Method.getParameterCount() because it is only available in Java 8. Use getParameterTypes().length instead.

src/main/java/com/zaxxer/hikari/util/PropertyElf.java

@@ -127,7 +127,7 @@ public final class PropertyElf
 
       List<Method> methods = Arrays.asList(target.getClass().getMethods());
       for (Method method : methods) {
-         if (method.getName().equals(methodName) && method.getParameterCount() == 1) {
+         if (method.getName().equals(methodName) && method.getParameterTypes().length == 1) {
             writeMethod = method;
             break;
          }
@@ -136,7 +136,7 @@ public final class PropertyElf
       if (writeMethod == null) {
          methodName = "set" + propName.toUpperCase();
          for (Method method : methods) {
-            if (method.getName().equals(methodName) && method.getParameterCount() == 1) {
+            if (method.getName().equals(methodName) && method.getParameterTypes().length == 1) {
                writeMethod = method;
                break;
             }