8193818 : Remove unused single_step field from java.lang.Thread

[David Holmes]

On 15/02/2018 9:42 PM, Alan Bateman wrote:
> On 19/12/2017 11:06, Alan Bateman wrote:
>> I've been going through the fields in java.lang.Thread and I'm 
>> wondering if this field can be removed:
>>
>>     /* Whether or not to single_step this thread. */
>>     private boolean     single_step;
>>
>> This field was used in the original Classic VM (pre-OpenJDK history). 
>> It doesn't appear to be used in the HotSpot VM.
>>
>> Does anyone know of any reason to keep it? Are there other VMs using 
>> it by any chance?
> No one screamed so I'd like to go ahead and remove this field. I've 
> created JDK-8193818 to track it, the change (below) is trivial.

Looks good to me :)

Thanks,
David

> -Alan
> 
> 
> --- a/src/java.base/share/classes/java/lang/Thread.java
> +++ b/src/java.base/share/classes/java/lang/Thread.java
> @@ -1,5 +1,5 @@
>   /*
> - * Copyright (c) 1994, 2017, Oracle and/or its affiliates. All rights 
> reserved.
> + * Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights 
> reserved.
>    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
>    *
>    * This code is free software; you can redistribute it and/or modify it
> @@ -150,9 +150,6 @@
>       private Thread         threadQ;
>       private long           eetop;
> 
> -    /* Whether or not to single_step this thread. */
> -    private boolean     single_step;
> -
>       /* Whether or not the thread is a daemon thread. */
>       private boolean     daemon = false;