Modernize chill-java for Java 17

chill-java/src/main/java/com/twitter/chill/ClassRegistrar.java

@@ -35,14 +35,9 @@ public ClassRegistrar(Class<T> cls) {
 
   @Override
   public boolean equals(Object that) {
-    if(null == that) {
-      return false;
-    }
-    else if(that instanceof ClassRegistrar) {
-      return klass.equals(((ClassRegistrar)that).klass);
-    }
-    else {
-      return false;
+    if (that instanceof ClassRegistrar<?> other) {
+      return klass.equals(other.klass);
     }
+    return false;
   }
 }

chill-java/src/main/java/com/twitter/chill/ReflectingDefaultRegistrar.java

@@ -39,15 +39,9 @@ public ReflectingDefaultRegistrar(Class<T> cls, Class<? extends Serializer<?>> s
 
   @Override
   public boolean equals(Object that) {
-    if(null == that) {
-      return false;
-    }
-    else if(that instanceof ReflectingDefaultRegistrar) {
-      return klass.equals(((ReflectingDefaultRegistrar)that).klass) &&
-        serializerKlass.equals(((ReflectingDefaultRegistrar)that).serializerKlass);
-    }
-    else {
-      return false;
+    if (that instanceof ReflectingDefaultRegistrar<?> other) {
+      return klass.equals(other.klass) && serializerKlass.equals(other.serializerKlass);
     }
+    return false;
   }
 }

chill-java/src/main/java/com/twitter/chill/ReflectingRegistrar.java

@@ -50,15 +50,9 @@ public void apply(Kryo k) {
 
   @Override
   public boolean equals(Object that) {
-    if(null == that) {
-      return false;
-    }
-    else if(that instanceof ReflectingRegistrar) {
-      return klass.equals(((ReflectingRegistrar)that).klass) &&
-        serializerKlass.equals(((ReflectingRegistrar)that).serializerKlass);
-    }
-    else {
-      return false;
+    if (that instanceof ReflectingRegistrar<?> other) {
+      return klass.equals(other.klass) && serializerKlass.equals(other.serializerKlass);
     }
+    return false;
   }
 }

chill-java/src/main/java/com/twitter/chill/config/ConfiguredInstantiator.java

@@ -103,16 +103,8 @@ static KryoInstantiator reflect(Class<? extends KryoInstantiator> instClass, Con
         return instClass.getDeclaredConstructor().newInstance();
       }
     }
-    catch(NoSuchMethodException x) {
-      throw new ConfigurationException(x);
-    }
-    catch(InstantiationException x) {
-      throw new ConfigurationException(x);
-    }
-    catch(IllegalAccessException x) {
-      throw new ConfigurationException(x);
-    }
-    catch(InvocationTargetException x) {
+    catch (NoSuchMethodException | InstantiationException |
+           IllegalAccessException | InvocationTargetException x) {
       throw new ConfigurationException(x);
     }
   }
@@ -153,17 +145,10 @@ protected static String serialize(Kryo k, KryoInstantiator ki) {
     return Base64.encodeBytes(out.toBytes());
   }
 
-  /** Simple class to hold the cached copy of the latest kryo instantiator.
-   * As well as its corresponding base64 encoded data.
+  /** Simple record to hold the cached copy of the latest kryo instantiator
+   * along with its corresponding base64 encoded data.
    */
-  private static class CachedKryoInstantiator {
-    public final KryoInstantiator kryoInstantiator;
-    public final String base64Value;
-    public CachedKryoInstantiator(KryoInstantiator ki, String bv) {
-      kryoInstantiator = ki;
-      base64Value = bv;
-    }
-  }
+  private record CachedKryoInstantiator(KryoInstantiator kryoInstantiator, String base64Value) {}
 
   private static CachedKryoInstantiator cachedKryoInstantiator = null;
 

chill-java/src/main/java/com/twitter/chill/config/JavaMapConfig.java

@@ -19,29 +19,28 @@
 import java.util.Map;
 
 /**
- * This takes a raw Map and calls toString on the objects before returning them as values
+ * This takes a Map and calls toString on the objects before returning them as values
  */
 public class JavaMapConfig extends Config {
 
-  final Map conf;
-  public JavaMapConfig(Map conf) {
-    this.conf = conf;
+  final Map<String, Object> conf;
+
+  public JavaMapConfig(Map<String, ?> conf) {
+    // We need to store as Map<String, Object> to allow put() with String values
+    this.conf = new java.util.HashMap<>(conf);
   }
+
   public JavaMapConfig() {
-    this(new java.util.HashMap<String, String>());
+    this.conf = new java.util.HashMap<>();
   }
-  /** Return null if this key is undefined */
+
   /** Return null if this key is undefined */
   @Override
   public String get(String key) {
     Object value = conf.get(key);
-    if(null != value) {
-      return value.toString();
-    }
-    else {
-      return null;
-    }
+    return value != null ? value.toString() : null;
   }
+
   @Override
   public void set(String key, String value) {
     conf.put(key, value);

chill-java/src/main/java/com/twitter/chill/config/ReflectingInstantiator.java

@@ -59,11 +59,10 @@ public ReflectingInstantiator(Config conf) throws ConfigurationException {
       // Make sure we can make a newKryo, this throws a runtime exception if not.
       newKryoWithEx();
     }
-    catch(ClassNotFoundException x) { throw new ConfigurationException(x); }
-    catch(InstantiationException x) { throw new ConfigurationException(x); }
-    catch(IllegalAccessException x) { throw new ConfigurationException(x); }
-    catch(NoSuchMethodException x) { throw new ConfigurationException(x); }
-    catch(java.lang.reflect.InvocationTargetException x) { throw new ConfigurationException(x); }
+    catch (ClassNotFoundException | InstantiationException | IllegalAccessException |
+           NoSuchMethodException | InvocationTargetException x) {
+      throw new ConfigurationException(x);
+    }
   }
 
   /** Create an instance using the defaults for non-listed params */
@@ -92,12 +91,12 @@ public ReflectingInstantiator(Class<? extends Kryo> kryoClass,
     this.regRequired = regRequired;
     this.skipMissing = skipMissing;
 
-    this.registrations = new ArrayList<IKryoRegistrar>();
-    for(IKryoRegistrar cr: classRegistrations) { this.registrations.add(cr); }
-    for(IKryoRegistrar rr: registrations) { this.registrations.add(rr); }
+    this.registrations = new ArrayList<>();
+    for (IKryoRegistrar cr : classRegistrations) { this.registrations.add(cr); }
+    for (IKryoRegistrar rr : registrations) { this.registrations.add(rr); }
 
-    defaultRegistrations = new ArrayList<ReflectingDefaultRegistrar>();
-    for(ReflectingDefaultRegistrar rdr: defaults) { defaultRegistrations.add(rdr); }
+    defaultRegistrations = new ArrayList<>();
+    for (ReflectingDefaultRegistrar rdr : defaults) { defaultRegistrations.add(rdr); }
   }
 
   public void set(Config conf) throws ConfigurationException {
@@ -131,10 +130,10 @@ public Kryo newKryo() {
     try {
       return newKryoWithEx();
     }
-    catch(InstantiationException x) { throw new RuntimeException(x); }
-    catch(IllegalAccessException x) { throw new RuntimeException(x); }
-    catch(NoSuchMethodException x) { throw new RuntimeException(x); }
-    catch(java.lang.reflect.InvocationTargetException x) { throw new RuntimeException(x); }
+    catch (InstantiationException | IllegalAccessException |
+           NoSuchMethodException | InvocationTargetException x) {
+      throw new RuntimeException(x);
+    }
   }
 
   /** All keys are prefixed with this string */
@@ -192,7 +191,7 @@ public Kryo newKryo() {
 
   protected List<? extends IKryoRegistrar> buildRegistrars(String base, boolean isAddDefault)
     throws ConfigurationException {
-      List<IKryoRegistrar> builder = new ArrayList<IKryoRegistrar>();
+      List<IKryoRegistrar> builder = new ArrayList<>();
 
       if (base == null)
           return builder;
@@ -240,19 +239,13 @@ protected String registrarsToString(Iterable<? extends IKryoRegistrar> registrar
           builder.append(":");
       isFirst = false;
       String part = null;
-      if(reg instanceof ClassRegistrar) {
-        ClassRegistrar r = (ClassRegistrar)reg;
+      if (reg instanceof ClassRegistrar<?> r) {
         part = r.getRegisteredClass().getName();
-      }
-      else if(reg instanceof ReflectingRegistrar) {
-        ReflectingRegistrar r = (ReflectingRegistrar)reg;
+      } else if (reg instanceof ReflectingRegistrar<?> r) {
         part = r.getRegisteredClass().getName() + "," + r.getSerializerClass().getName();
-      }
-      else if(reg instanceof ReflectingDefaultRegistrar) {
-        ReflectingDefaultRegistrar r = (ReflectingDefaultRegistrar)reg;
+      } else if (reg instanceof ReflectingDefaultRegistrar<?> r) {
         part = r.getRegisteredClass().getName() + "," + r.getSerializerClass().getName();
-      }
-      else {
+      } else {
         throw new ConfigurationException("Unknown type of reflecting registrar: " + reg.getClass().getName());
       }
       builder.append(part);
@@ -269,21 +262,15 @@ public int hashCode() {
 
   @Override
   public boolean equals(Object that) {
-    if(null == that) {
-      return false;
-    }
-    else if(that instanceof ReflectingInstantiator) {
-      ReflectingInstantiator thatri = (ReflectingInstantiator)that;
-      return (regRequired == thatri.regRequired) &&
-        (skipMissing == thatri.skipMissing) &&
-        kryoClass.equals(thatri.kryoClass) &&
-        instStratClass.equals(thatri.instStratClass) &&
-        registrations.equals(thatri.registrations) &&
-        defaultRegistrations.equals(thatri.defaultRegistrations);
-    }
-    else {
-      return false;
+    if (that instanceof ReflectingInstantiator other) {
+      return regRequired == other.regRequired &&
+        skipMissing == other.skipMissing &&
+        kryoClass.equals(other.kryoClass) &&
+        instStratClass.equals(other.instStratClass) &&
+        registrations.equals(other.registrations) &&
+        defaultRegistrations.equals(other.defaultRegistrations);
     }
+    return false;
   }
 
 }

chill-java/src/main/java/com/twitter/chill/java/IterableRegistrarSerializer.java

@@ -33,7 +33,7 @@ public void write(Kryo kryo, Output output, IterableRegistrar obj) {
     kryo.writeClassAndObject(output, null);
   }
   public IterableRegistrar read(Kryo kryo, Input input, Class<IterableRegistrar> type) {
-    ArrayList<IKryoRegistrar> krs = new ArrayList<IKryoRegistrar>();
+    var krs = new ArrayList<IKryoRegistrar>();
     IKryoRegistrar thisKr = (IKryoRegistrar)kryo.readClassAndObject(input);
     while(thisKr != null) {
       krs.add(thisKr);