Specification of SSLSocket#setEnabledCipherSuites says,
“Throws: IllegalArgumentException - when one or more of the ciphers named by the parameter is not supported, or when the parameter is null.”

However,

with JDKb20, (refer [1] for code)
SSLSocket#setEnabledCipherSuites (new String[] {“”} ) // empty string
Is accepted and not throwing IllegalArgumentException

With JDKb15 (refer to [2] for code)
SSLSocket#setEnabledCipherSuites(new String[]{“”}) throws IllegalArgumentException

[1]
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JDK-11\20\jdk-11\bin\jshell
| Welcome to JShell -- Version 11-ea
| For an introduction type: /help intro

jshell> import javax.net.ssl.*

jshell> SSLContext ctx = SSLContext.getInstance("TLS")
ctx ==> javax.net.ssl.SSLContext@7113b13f

jshell> ctx.init(null,null,null)

jshell> SSLSocket sslSocket = (SSLSocket)ctx.getSocketFactory().createSocket()
sslSocket ==> Socket[unconnected]

jshell> sslSocket.setEnabledCipherSuites(new String[]{""})

jshell>
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[2]
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JDK-11\15\jdk-11\bin\jshell
| Welcome to JShell -- Version 11-ea
| For an introduction type: /help intro

jshell> import javax.net.ssl.*

jshell> SSLContext ctx = SSLContext.getInstance("TLS")
ctx ==> javax.net.ssl.SSLContext@587d1d39

jshell> ctx.init(null,null,null)

jshell> SSLSocket sslSocket = (SSLSocket) ctx.getSocketFactory().createSocket()
sslSocket ==> 73d4cc9e[SSL_NULL_WITH_NULL_NULL: Socket[unconnected]]

jshell> sslSocket.setEnabledCipherSuites(new String[] {""} )
| Exception java.lang.IllegalArgumentException: Unsupported ciphersuite
| at CipherSuite.valueOf (CipherSuite.java:283)
| at CipherSuiteList.<init> (CipherSuiteList.java:82)
| at SSLSocketImpl.setEnabledCipherSuites (SSLSocketImpl.java:2473)
| at (#5:1)
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