8258422: Cleanup unnecessary null comparison before instanceof check in java.base

use instanceof pattern matching

Author: turbanoff

src/java.base/share/classes/java/io/File.java

@@ -2190,8 +2190,8 @@ public int compareTo(File pathname) {
      *          {@code false} otherwise
      */
     public boolean equals(Object obj) {
-        if (obj instanceof File) {
-            return compareTo((File)obj) == 0;
+        if (obj instanceof File file) {
+            return compareTo(file) == 0;
         }
         return false;
     }

src/java.base/share/classes/java/lang/reflect/Constructor.java

@@ -308,8 +308,7 @@ public Type[] getGenericExceptionTypes() {
      * same formal parameter types.
      */
     public boolean equals(Object obj) {
-        if (obj instanceof Constructor) {
-            Constructor<?> other = (Constructor<?>)obj;
+        if (obj instanceof Constructor<?> other) {
             if (getDeclaringClass() == other.getDeclaringClass()) {
                 return equalParamTypes(parameterTypes, other.parameterTypes);
             }

src/java.base/share/classes/java/lang/reflect/Field.java

@@ -279,8 +279,7 @@ public Type getGenericType() {
      * and type.
      */
     public boolean equals(Object obj) {
-        if (obj instanceof Field) {
-            Field other = (Field)obj;
+        if (obj instanceof Field other) {
             return (getDeclaringClass() == other.getDeclaringClass())
                 && (getName() == other.getName())
                 && (getType() == other.getType());

src/java.base/share/classes/java/lang/reflect/Method.java

@@ -358,8 +358,7 @@ public Type[] getGenericExceptionTypes() {
      * and formal parameter types and return type.
      */
     public boolean equals(Object obj) {
-        if (obj instanceof Method) {
-            Method other = (Method)obj;
+        if (obj instanceof Method other) {
             if ((getDeclaringClass() == other.getDeclaringClass())
                 && (getName() == other.getName())) {
                 if (!returnType.equals(other.getReturnType()))

src/java.base/share/classes/java/net/Inet4Address.java

@@ -352,8 +352,8 @@ public int hashCode() {
      * @see     java.net.InetAddress#getAddress()
      */
     public boolean equals(Object obj) {
-        return (obj instanceof Inet4Address) &&
-            (((InetAddress)obj).holder().getAddress() == holder().getAddress());
+        return (obj instanceof Inet4Address inet4Address) &&
+            inet4Address.holder().getAddress() == holder().getAddress();
     }
 
     // Utilities

src/java.base/share/classes/sun/net/www/protocol/http/Negotiator.java

@@ -66,8 +66,8 @@ static Negotiator getNegotiator(HttpCallerInfo hci) {
         } catch (ReflectiveOperationException roe) {
             finest(roe);
             Throwable t = roe.getCause();
-            if (t instanceof Exception)
-                finest((Exception)t);
+            if (t instanceof Exception exception)
+                finest(exception);
             return null;
         }
     }

src/java.base/share/classes/sun/nio/fs/PollingWatchService.java

@@ -149,8 +149,8 @@ public PollingWatchKey run() throws IOException {
                 });
         } catch (PrivilegedActionException pae) {
             Throwable cause = pae.getCause();
-            if (cause instanceof IOException)
-                throw (IOException)cause;
+            if (cause instanceof IOException ioe)
+                throw ioe;
             throw new AssertionError(pae);
         }
     }

src/java.base/windows/classes/sun/nio/fs/WindowsPath.java

@@ -798,8 +798,8 @@ public int compareTo(Path obj) {
 
     @Override
     public boolean equals(Object obj) {
-        if (obj instanceof WindowsPath) {
-            return compareTo((Path)obj) == 0;
+        if (obj instanceof WindowsPath path) {
+            return compareTo(path) == 0;
         }
         return false;
     }