Webkit plugin loading causes SIGABRT and crash

Description:

Application with enabled plugin is receives SIGABRT in case of loading plugin from library from Oracle Java Development Kit 10 and crashes.

Steps to reproduce:

1. use Manjaro Linux or Arch Linux with qt5-webkit, Oracle jdk9 or jdk10 and nixnote2 installed (see environment)
2. Start nixnote2 from cli
3. nixnote2 crashes

Reproducible allways. Note: Manjaro Linux is clone of Arch Linux with rolling updates. This issue was discovered in mid of April at up-to-date system and persists still.

Workaround:

• uninstall Oracle Java Development Kit package (jdk package from AUR) - versions 10 and 9
• or compile Nixnote without enabled plugins

Deeper analysis:

• see also https://aur.archlinux.org/packages/nixnote2/#comment-642836 or attached strace.txt, which shows as last opened library the lib from jdk10
• after cloning of sources of NixNote2, compiling with debug mode and running with strace or running from QtCreator got me more details. In nixnote2 sources I have found following content in file nbrowserwindow.cpp, in line 207 there is:

editor->page()->settings()->setAttribute(QWebSettings::PluginsEnabled, true);

where the class attributes are following instances:

editor - nixnote2 class NWebView (imho not relevant for this issue)
page - QWebPage
settings - QWebSettings

If the mentioned code line is commented and nixnote is recompiled, there is no crash neither sigabrt and nixnote runs without problems even, when there is jdk9 or jdk10 (Oracle Java Development Kit) package installed, which causes crash during loading attempt.