Perhaps you should try some spelling variations:
"using java core snippets" » "using data core snippets"
"trinh do trac snippets" » "trinh ky trac snippets", "trinh hoi trac snippets", "trinh bo trach snippets", "trinh co trach snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code snippets"

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"using java core snippets\") OR (\"trinh do trac snippets\"))) OR (\"locating bug code snippets\"))~".
• Removing quotes may allow a broader search: (((( using java core snippets ) OR ( trinh do trac snippets ))) OR ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("using java core snippets") OR ("trinh do trac snippets"))) OR ("locating bug code snippets"))*.