ITW classloding seems to inefficiently look up classes. For example, it looks to download this JDK class from the jnlp codebase location:

[net.sourceforge.jnlp.runtime.JNLPProxySelector.select(JNLPProxySelector.java:183)] NETX Thread# 22f72b5c, name AWT-EventQueue-1 Selecting proxy for: https://host/path/javax/swing/plaf/BorderUIResource.class^M

javax.net.ssl|FINE|5B|AWT-EventQueue-1|2022-12-09 12:29:32.725 IST|SSLCipher.java:1720|Plaintext before ENCRYPTION (
  0000: 48 45 41 44 20 2F 64 65   73 6D 6C 73 2F 6A 61 76  HEAD /path/jav
  0010: 61 78 2F 73 77 69 6E 67   2F 70 6C 61 66 2F 42 6F  ax/swing/plaf/Bo
  0020: 72 64 65 72 55 49 52 65   73 6F 75 72 63 65 2E 63  rderUIResource.c
  0030: 6C 61 73 73 20 48 54 54   50 2F 31 2E 31 0D 0A 43  lass HTTP/1.1..C
  0040: 61 63 68 65 2D 43 6F 6E   74 72 6F 6C 3A 20 6E 6F  ache-Control: no

javax.net.ssl|FINE|5B|AWT-EventQueue-1|2022-12-09 12:29:32.964 IST|SSLCipher.java:1622|Plaintext after DECRYPTION (
  0000: 48 54 54 50 2F 31 2E 31   20 34 30 34 20 4E 6F 74  HTTP/1.1 404 Not
  0010: 20 46 6F 75 6E 64 0D 0A   44 61 74 65 3A 20 46 72   Found..Date: Fr

Apparently, ITW eventually finds the classes it needs after thousands of connections.