We need to use the new function setFlowInstanceTitle to set composite instance title in 12c environment.
If JDeveloper doesn’t show this function or gives a warning that it is not able to find the function, we need to patch SOA (including JDeveloper) with latest bundle patch.
If we deploy the composite, ignoring the warning, during runtime, we will get the following error
<bpelFault><faultType>0</faultType><subLanguageExecutionFault xmlns="http://docs.oasis-open.org/wsbpel/2.0/process/executable"><part name="summary"><summary> An error occurs while processing the XPath expression; the expression is oraext:setFlowInstanceTitle('some value').</summary></part><part name="detail"><detail>XPath expression failed to execute. An error occurs while processing the XPath expression; the expression is oraext:setFlowInstanceTitle('a'). The XPath expression failed to execute; the reason was: Extension function error: Method not found 'setFlowInstanceTitle'
Install latest bundle patch for SOA to resolve the issue. After applying the patch, JDeveloper will show this function under “Advanced Functions”.
It is good to install latest Bundle Patch as it will have other bug fixes too. If a fix to this problem alone is needed, we can download and install “Patch 18310693”.
To apply latest patch please refer this How to apply bundle patch using OPatch for SOA post.