Problems with UTF-8 encoding - web-project

I'm aware that this question was already asked a couple of times, but I didn't get the problem solved even with the hints mentioned in other posts. For a small webproject I created some html/jsp pages that are calling links to two servlets. The servlets themselves are talking to a PostgreSQL database. Everything is working instead of the encoding. When I'm typing in special characters (UTF-8) like "ü", "ä" or "ö", I can see them:

• correctly inserted into the web page
• correctly listed inside of the java objects (Debug mode) correctly inserted into the database

Since the web tool reloads the data with every change (a simultaneously work should be provided), I can also see the following steps working:

• after the tool was re-loading the data from the database, the special characters are listed inside of the java objects (Debug mode)
• the attribute inside of the request-object has the correct value

Nevertheless, after reload the data is not shown correctly anymore inside the web page - just cryptic signs. Can you please support? I already checked the following points:

• encoding of Eclipse
• encoding of database
• encoding of servlets
• encoding of the application server (Wildfly)
• encoding of the JSP files
• encoding inside of Chrome

Best greetings, Jesfreric