Some tools are Java applications (or contain a Java application) and require a runnable Java environment on your computer. These applications will be downloaded, maybe asking for confimation to execute and start in a separate window (outside and independant of the web brwoser). If the application starts -but hangs- the amount of memory for the Java machine may not be sufficant. It could be a good idea to enlarge the usable memory to at least 256MB which should be sufficiant for most applications.

To execute a Java Application direct from this webpage an application "icedtea" must be installed locally on your PC. It will run the downloaded "jnlp" file. But in newer environments the execution of this "jnlp" files from a server is getting more restrictive. To avoid problems it may help to change the setting of "jdk.jar.disabledAlgorithms" in the file "java.security" and remove the entry "SHA1 denyAfter 2019-01-01". Like from

jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024, \
DSA keySize < 1024, SHA1 denyAfter 2019-01-01, \
include jdk.disabled.namedCurves

to

jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024, \
DSA keySize < 1024, \
include jdk.disabled.namedCurves