The Java observability docs at Observability - Java SDK feature guide | Temporal Documentation reference using setSearchAttributes but this function is deprecated in favor of setTypedSearchAttributes. The latter is not dcoumented at all.
In addition, the docs reference some type ListWorkflowExecutions which I think should be WorkflowClient.listExecutions(query).
For the search attributes, yes, that is true, we have sample you could use: samples-java/core/src/main/java/io/temporal/samples/hello/HelloTypedSearchAttributes.java at main · temporalio/samples-java · GitHub
For list executions, yes this is a new convenience method that does pagination under the hood for you, you can still use ListWorkflowExecutions if you wish, actually could be useful if you are looking for just the first page of results for longer event histories in some cases.