java: remove multiple checks for JVM version

- make sure minimum is now Java 17

Author: jknack

handlebars/src/main/java/com/github/jknack/handlebars/Handlebars.java

@@ -157,18 +157,6 @@ public boolean equals(final Object obj) {
    */
   public static class Utils {
 
-    /** Java 14. */
-    private static final int JAVA_14 = 14;
-
-    /** Current Java version: 8, 11, 15, etc. */
-    public static final int javaVersion = javaVersion();
-
-    /** True when running on Java 14 or higher. */
-    public static final boolean javaVersion14 = javaVersion() >= JAVA_14;
-
-    /** Prefix for Java version: 1.8 (mostly). */
-    private static final String VERSION_PREFIX = "1.";
-
     /**
      * Evaluate the given object and return true is the object is considered empty. Nulls, empty
      * list or array and false values are considered empty.
@@ -221,11 +209,6 @@ public static CharSequence escapeExpression(final CharSequence input) {
       return EscapingStrategy.DEF.escape(input);
     }
 
-    static int javaVersion() {
-      String version = System.getProperty("java.specification.version").trim();
-      return Integer.parseInt(version.replace(VERSION_PREFIX, ""));
-    }
-
     /**
      * Throws any throwable 'sneakily' - you don't need to catch it, nor declare that you throw it
      * onwards. The exception is still thrown - javac will just stop whining about it.

handlebars/src/main/java/com/github/jknack/handlebars/ValueResolver.java

@@ -5,9 +5,6 @@
  */
 package com.github.jknack.handlebars;
 
-import static java.util.Arrays.asList;
-import static java.util.Collections.unmodifiableList;
-
 import java.util.List;
 import java.util.Map.Entry;
 import java.util.Set;
@@ -66,13 +63,7 @@ public interface ValueResolver {
    * @return Immutable list of value resolvers.
    */
   static List<ValueResolver> defaultValueResolvers() {
-    if (Handlebars.Utils.javaVersion14) {
-      return unmodifiableList(
-          asList(
-              MapValueResolver.INSTANCE,
-              JavaBeanValueResolver.INSTANCE,
-              MethodValueResolver.INSTANCE));
-    }
-    return unmodifiableList(asList(MapValueResolver.INSTANCE, JavaBeanValueResolver.INSTANCE));
+    return List.of(
+        MapValueResolver.INSTANCE, JavaBeanValueResolver.INSTANCE, MethodValueResolver.INSTANCE);
   }
 }

handlebars/src/main/java/com/github/jknack/handlebars/internal/BaseTemplate.java

@@ -14,7 +14,6 @@
 import java.io.Writer;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
-import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
@@ -241,31 +240,12 @@ private Object invokeDefaultMethod(
               final Object proxy,
               final Object... args)
               throws Throwable {
-            if (Handlebars.Utils.javaVersion14) {
-              MethodType methodType =
-                  MethodType.methodType(method.getReturnType(), method.getParameterTypes());
-              return MethodHandles.lookup()
-                  .findSpecial(lookupClass, method.getName(), methodType, lookupClass)
-                  .bindTo(proxy)
-                  .invokeWithArguments(args);
-            } else {
-              // Jumping through these hoops is needed because calling unreflectSpecial
-              // requires
-              // that the lookup instance have private access to the special caller. None of
-              // the
-              // static factory methods for Lookup will give us an instance with the access
-              // modes
-              // we need, so we work around it by calling the private constructor via
-              // reflection.
-              Constructor<MethodHandles.Lookup> constructor =
-                  MethodHandles.Lookup.class.getDeclaredConstructor(Class.class, int.class);
-              constructor.setAccessible(true);
-              return constructor
-                  .newInstance(lookupClass, -1 /* trusted */)
-                  .unreflectSpecial(method, lookupClass)
-                  .bindTo(proxy)
-                  .invokeWithArguments(args);
-            }
+            MethodType methodType =
+                MethodType.methodType(method.getReturnType(), method.getParameterTypes());
+            return MethodHandles.lookup()
+                .findSpecial(lookupClass, method.getName(), methodType, lookupClass)
+                .bindTo(proxy)
+                .invokeWithArguments(args);
           }
 
           @Override

handlebars/src/test/java/com/github/jknack/handlebars/AbstractTest.java

@@ -10,7 +10,6 @@
 import java.io.IOException;
 import java.util.LinkedHashMap;
 import java.util.Map.Entry;
-import java.util.function.Predicate;
 
 import org.yaml.snakeyaml.Yaml;
 
@@ -188,10 +187,4 @@ protected Handlebars newHandlebars() {
     }
     return model;
   }
-
-  public void withJava(Predicate<Integer> predicate, Task task) throws IOException {
-    if (predicate.test(Handlebars.Utils.javaVersion)) {
-      task.run();
-    }
-  }
 }

handlebars/src/test/java/com/github/jknack/handlebars/JavaVersionTest.java

@@ -56,12 +56,7 @@ public void testBadPattern() throws IOException {
   @Test
   public void testStyle() throws IOException {
     DateTime dateTime = new DateTime().withDate(1995, 7, 4).withTime(14, 32, 12, 0);
-    withJava(
-        version -> version <= 8,
-        () -> shouldCompileTo("{{jodaStyleHelper this \"SS\"}}", dateTime, "7/4/95 2:32 PM"));
-    withJava(
-        version -> version >= 9,
-        () -> shouldCompileTo("{{jodaStyleHelper this \"SS\"}}", dateTime, "7/4/95, 2:32 PM"));
+    shouldCompileTo("{{jodaStyleHelper this \"SS\"}}", dateTime, "7/4/95, 2:32 PM");
   }
 
   @Test