Optimize the usage of Charset

[6U-U9]

Constant charset defined by String (for example, "UTF-8") can be replaced with the predefined StandardCharsets.UTF_8 code.
The code after the fix may work faster, because the charset lookup becomes unnecessary.

[6U-U9]

#4024 this Issue is for PR Replace Charset.forName("UTF-8") with StandardCharsets.UTF_8 #4024

[github-actions]

This issue is stale because it has been open for 365 days with no activity. It will be closed in 3 days if no further activity occurs.

[github-actions]

This issue was closed because it has been inactive for 3 days since being marked as stale.