I tried hacking (I don't like having to do this).
I removed the line below from the WebRatio.ini file
-XX:+UseFastAccessorMethods
Now I get a load of errors including
!SESSION 2020-03-30 15:56:57.578 -----------------------------------------------
eclipse.buildId=unknown
java.version=14
java.vendor=Oracle Corporation
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=en_GB
Command-line arguments: -os linux -ws gtk -arch x86_64
!ENTRY com.webratio.bpm.core 4 0 2020-03-30 15:57:01.192
!MESSAGE FrameworkEvent ERROR
!STACK 0
org.osgi.framework.BundleException: Could not resolve module: com.webratio.bpm.core [13]
Unresolved requirement: Require-Bundle: com.webratio.commons.mf.model
-> Bundle-SymbolicName: com.webratio.commons.mf.model; bundle-version="8.10.5.201910082137"; singleton:="true"
com.webratio.commons.mf.model [98]
Unresolved requirement: Require-Bundle: com.webratio.commons.transform; visibility:="reexport"
-> Bundle-SymbolicName: com.webratio.commons.transform; bundle-version="8.10.5.201910082137"
com.webratio.commons.transform [105]
Unresolved requirement: Require-Bundle: com.webratio.commons.dom4j
-> Bundle-SymbolicName: com.webratio.commons.dom4j; bundle-version="1.0.0.201810081230"
com.webratio.commons.dom4j [28]
Unresolved requirement: Require-Bundle: com.webratio.commons.lib.jackson2
-> Bundle-SymbolicName: com.webratio.commons.lib.jackson2; bundle-version="2.7.1"
com.webratio.commons.lib.jackson2 [62]
Unresolved requirement: Require-Capability: osgi.ee; filter:="(&(osgi.ee=JavaSE)(version=1.7))"
at org.eclipse.osgi.container.Module.start(Module.java:434)
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1582)
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1561)
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.doContainerStartLevel(ModuleContainer.java:1533)
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1476)
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)
The last one before the installer crashes being
!ENTRY org.eclipse.osgi 4 0 2020-03-30 15:57:17.588
!MESSAGE Application error
!STACK 1
java.lang.NoClassDefFoundError: org/w3c/dom/stylesheets/StyleSheet
at org.eclipse.e4.ui.css.swt.internal.theme.ThemeEngineManager.getCSSSWTEngine(ThemeEngineManager.java:41)
at org.eclipse.e4.ui.css.swt.internal.theme.ThemeEngineManager.getEngineForDisplay(ThemeEngineManager.java:30)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createThemeEngine(PartRenderingEngine.java:1428)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.initializeStyling(PartRenderingEngine.java:1281)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1036)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1032)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:148)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:636)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:579)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:135)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:380)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:235)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:648)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:603)
at org.eclipse.equinox.launcher.Main.run(Main.java:1465)
at org.eclipse.equinox.launcher.Main.main(Main.java:1438)
Caused by: java.lang.ClassNotFoundException: org.w3c.dom.stylesheets.StyleSheet cannot be found by org.eclipse.e4.ui.css.core_0.10.100.v20140424-2042
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:432)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
... 26 more