If you installed WSClient on Fedora platform, such as Fedora21, the WSClient maybe does not work with the default OpenJDK, it will appear the below error(Figure 1).
Because the Java runtime on Fedora not be installed whole. You can install the OpenJDK again with the below steps (Figure 2).
1) Click Software icon on the left status bar.
2) Search "OpenJDK" and install "The OpenJDK runtime environment". Figure 3.
3) Run the WSClient again after the OpenJDK install successfully. Figure4.