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

@@ -120,11 +120,11 @@
             }
             sb.append(sj.toString());
             sb.append(')');
 
             if (exceptionTypes.length > 0) {
-                StringJoiner joiner = new StringJoiner(",", "throws ", "");
+                StringJoiner joiner = new StringJoiner(",", " throws ", "");
                 for (Class<?> exceptionType : exceptionTypes) {
                     joiner.add(exceptionType.getTypeName());
                 }
                 sb.append(joiner.toString());
             }