[standalone@localhost:9990 /] :validate-operation                                                  
{
    "outcome" => "failed",
    "failure-description" => "WFLYCTL0158: Operation handler failed: java.util.NoSuchElementException: No child 'value' exists",
    "rolled-back" => true
}

08:58:13,409 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 17) WFLYCTL0013: Operation ("validate-operation") failed - address: ([]): java.util.NoSuchElementException: No child 'value' exists
	at org.jboss.dmr.ModelValue.requireChild(ModelValue.java:387)
	at org.jboss.dmr.ObjectModelValue.requireChild(ObjectModelValue.java:302)
	at org.jboss.dmr.ModelNode.require(ModelNode.java:875)
	at org.jboss.as.controller.operations.common.ValidateOperationHandler.execute(ValidateOperationHandler.java:91)
	at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:940)
	at org.jboss.as.controller.AbstractOperationContext.processStages(AbstractOperationContext.java:683)
	at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:382)
	at org.jboss.as.controller.OperationContextImpl.executeOperation(OperationContextImpl.java:1363)
	at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:410)
	at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:232)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.doExecute(ModelControllerClientOperationHandler.java:213)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.access$300(ModelControllerClientOperationHandler.java:136)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:157)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:153)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:422)
	at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:149)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1.execute(ModelControllerClientOperationHandler.java:153)
	at org.jboss.as.protocol.mgmt.ManagementRequestContextImpl$1.doExecute(ManagementRequestContextImpl.java:70)
	at org.jboss.as.protocol.mgmt.ManagementRequestContextImpl$AsyncTaskRunner.run(ManagementRequestContextImpl.java:160)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
	at org.jboss.threads.JBossThread.run(JBossThread.java:320)

[standalone@localhost:9990 /] :validate-operation(value=nonsense)
{
    "outcome" => "failed",
    "failure-description" => "WFLYCTL0158: Operation handler failed: java.lang.IllegalArgumentException",
    "rolled-back" => true
}

09:01:10,367 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 19) WFLYCTL0013: Operation ("validate-operation") failed - address: ([]): java.lang.IllegalArgumentException
	at org.jboss.dmr.ModelValue.getChild(ModelValue.java:115)
	at org.jboss.dmr.ModelNode.get(ModelNode.java:861)
	at org.jboss.as.controller.operations.common.ValidateOperationHandler.execute(ValidateOperationHandler.java:92)
	at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:940)
	at org.jboss.as.controller.AbstractOperationContext.processStages(AbstractOperationContext.java:683)
	at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:382)
	at org.jboss.as.controller.OperationContextImpl.executeOperation(OperationContextImpl.java:1363)
	at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:410)
	at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:232)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.doExecute(ModelControllerClientOperationHandler.java:213)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.access$300(ModelControllerClientOperationHandler.java:136)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:157)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:153)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:422)
	at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:149)
	at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1.execute(ModelControllerClientOperationHandler.java:153)
	at org.jboss.as.protocol.mgmt.ManagementRequestContextImpl$1.doExecute(ManagementRequestContextImpl.java:70)
	at org.jboss.as.protocol.mgmt.ManagementRequestContextImpl$AsyncTaskRunner.run(ManagementRequestContextImpl.java:160)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
	at org.jboss.threads.JBossThread.run(JBossThread.java:320)

[standalone@localhost:9990 /] :validate-operation(value={"nonsense" => "nonsense"})
Failed to handle ':validate-operation(value={"nonsense" => "nonsense"})': java.lang.IllegalArgumentException