pipeline {
    agent any
    stages {
        stage ('PrintCommand') {
            steps {
                script {
                    def command = "try { println env.BUILD_NUMBER } catch (Exception ex) { println \"Error: ${ex.getMessage()}\" }"
                    println command
                }
            }
        }
    }
}

groovy.lang.MissingPropertyException: No such property: ex for class: WorkflowScript
	at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:53)
	at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.getProperty(ScriptBytecodeAdapter.java:458)
	at org.kohsuke.groovy.sandbox.impl.Checker$6.call(Checker.java:290)
	at org.kohsuke.groovy.sandbox.GroovyInterceptor.onGetProperty(GroovyInterceptor.java:68)
	at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onGetProperty(SandboxInterceptor.java:348)
	at org.kohsuke.groovy.sandbox.impl.Checker$6.call(Checker.java:288)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:292)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:268)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:268)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:268)
	at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.getProperty(SandboxInvoker.java:29)
	at com.cloudbees.groovy.cps.impl.PropertyAccessBlock.rawGet(PropertyAccessBlock.java:20)
	at WorkflowScript.run(WorkflowScript:7)
	at ___cps.transform___(Native Method)
	at com.cloudbees.groovy.cps.impl.PropertyishBlock$ContinuationImpl.get(PropertyishBlock.java:74)
	at com.cloudbees.groovy.cps.LValueBlock$GetAdapter.receive(LValueBlock.java:30)
	at com.cloudbees.groovy.cps.impl.PropertyishBlock$ContinuationImpl.fixName(PropertyishBlock.java:66)
	at sun.reflect.GeneratedMethodAccessor1524.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)
	at com.cloudbees.groovy.cps.impl.ConstantBlock.eval(ConstantBlock.java:21)
	at com.cloudbees.groovy.cps.Next.step(Next.java:83)
	at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:174)
	at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:163)
	at org.codehaus.groovy.runtime.GroovyCategorySupport$ThreadCategoryInfo.use(GroovyCategorySupport.java:129)
	at org.codehaus.groovy.runtime.GroovyCategorySupport.use(GroovyCategorySupport.java:268)
	at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:163)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.access$101(SandboxContinuable.java:34)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.lambda$run0$0(SandboxContinuable.java:59)
	at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.GroovySandbox.runInSandbox(GroovySandbox.java:136)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.run0(SandboxContinuable.java:58)
	at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:182)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:332)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$200(CpsThreadGroup.java:83)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:244)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:232)
	at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:64)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:131)
	at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
	at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:59)
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Finished: FAILURE

pipeline {
    agent any
    stages {
        stage ('PrintCommand') {
            steps {
                script {
                    def command = 'try { println env.BUILD_NUMBER } catch (Exception ex) { println \"Error: ${ex.getMessage()}\" }'
                    println command
                    evaluate command
                }
            }
        }
    }
}