src/java.base/share/classes/sun/nio/cs/ArrayDecoder.java

*** 30,35 ****
--- 30,39 ----
   * unmappable input.
   */
  
  public interface ArrayDecoder {
      int decode(byte[] src, int off, int len, char[] dst);
+ 
+     default boolean isASCIICompatible() {
+         return false;
+     }
  }