Reason for error: java.util.List and java.util.ArrayList packages were not imported.
Such as: ` 
Error: Multiple markers at this line
-ArrayList cannot be resolved to
a type
-List cannot be resolved to a
type
` Solution : Import the java.util.List and java.util.ArrayList packages. Be careful not to put the import package statement in front of package Myfirst_package, otherwise an error will be reported: Syntax error on token “package”, import expected. Such as:
wrong import,
correct import method :