ThinkOrSwim requires jre <= 8, setting that as the default is just inconvenient so I wrote a tiny bash script to help with it.
#!/bin/sh
# random optimizations collected over the years from forums and reddit
export _JAVA_OPTIONS="-Dsun.java2d.opengl=true"
export J2D_PIXMAPS=shared
export _JAVA_AWT_WM_NONREPARENTING=1
# zulu seems o give the best performance for me, ymmv.
export JAVA_HOME="/usr/lib/jvm/zulu-8"
export PATH="$JAVA_HOME/bin:$PATH"
# used the installer to install tos to ~/thinkorswim
~/thinkorswim/thinkorswim