Here is the array of all the Java reserved keywords (taken from here and keep being updated from here):

String keywords[] = { "abstract", "assert", "boolean", "break", "byte", "case", "catch", 
    "char", "class", "const", "continue", "default", "do", "double", "else", "extends", 
    "false", "final", "finally", "float", "for", "goto", "if", "implements", "import", 
    "instanceof", "int", "interface", "long", "native", "new", "null", "package", 
    "private", "protected", "public", "return", "short", "static", "strictfp", "super", 
    "switch", "synchronized", "this", "throw", "throws", "transient", "true", "try", 
    "void", "volatile", "while"
};

You have to navigate to the library where is Hashtable class using the JAVA_HOME system variable.

System.getenv("JAVA_HOME");

The java.util.Hashtable (and others) is located at %JAVA_HOME%/jre/lib/rt.jar library.

You have to find a way to extract the package, find the required file, decompile it and read lane by lane (using f.e. Regex). I recommend you to start reading answers of this question.

Unfortunately, there is NO other way.

DO NOT build SQL queries using string concatenation - you should be using bind parameters.

Your query string should be:

query="select * from books where BookName LIKE ?";

and then you can do something like:

Class.forName( "oracle.jdbc.OracleDriver" ); // If you are using the Oracle driver.

Connection con = DriverManager.getConnection(
  "jdbc:oracle:thin:@localhost:1521:XE",
  "username",
  "password"
);

final String query="select * from books where BookName LIKE ?";
PreparedStatement ps = conn.prepareStatement(query);            
ps.setString( 1, "%" + txt1.getText() + "%" );
ResultSet rs = ps.executeQuery();
// Loop through the result set.
// Close statement/connections

(you will need to handle exceptions, etc.)

and:

• You should not need to change the query to swap between MySQL and Oracle (just change the driver and connection string).
• You do not need to escape any single or double quotation marks in the input string.
• You are protected from SQL injection attacks.
• Oracle can cache the query with the bind parameter and does not have to re-parse / re-compile it when the bind parameter changes.

If you are going to write the query as a string then string literals are surrounded by single quotes (not double quotes) in SQL:

query="select * from books where BookName LIKE '%your_string%'";

and you need to make sure that any single quotes in your string are properly escaped (but just use a bind parameter instead).

From axis.apache.org

Basically, Pre-Sort the keywords and store it in an array and using Arrays.binarySearch on your keyword for the good'ol O(logn) complexity

import java.util.Arrays;

    public class MainDemo {
        static final String keywords[] = { "abstract", "assert", "boolean",
                "break", "byte", "case", "catch", "char", "class", "const",
                "continue", "default", "do", "double", "else", "extends", "false",
                "final", "finally", "float", "for", "goto", "if", "implements",
                "import", "instanceof", "int", "interface", "long", "native",
                "new", "null", "package", "private", "protected", "public",
                "return", "short", "static", "strictfp", "super", "switch",
                "synchronized", "this", "throw", "throws", "transient", "true",
                "try", "void", "volatile", "while" };

        public static boolean isJavaKeyword(String keyword) {
            return (Arrays.binarySearch(keywords, keyword) >= 0);
        }

        //Main method
        public static void main(String[] args) {
            System.out.println(isJavaKeyword("void"));

        }

    }

Output:

True

Alternatively, as users @typeracer,@holger suggested in the comments, you can use SourceVersion.isKeyword("void") which uses javax.lang.model.SourceVersion library and Hashset Data structure internally and keeps the list updated for you.

Classes don't have keyword "new" as a personal method or anything like that. It is the Java language itself that has the keyword "new". So in other words you put "new" in the code the compiler would recognize it and instantiate a new Object.

http://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.9- this link is the documentation of Java language, in section 3.9 it shows all the keywords.

Edit: Like others are saying, what the snippet of code in your question indicates an inner class, so for instance, like it says in http://docs.oracle.com/javase/tutorial/java/javaOO/nested.html

public class ShadowTest {

public int x = 0;

class FirstLevel {

    public int x = 1;

    void methodInFirstLevel(int x) {
        System.out.println("x = " + x);
        System.out.println("this.x = " + this.x);
        System.out.println("ShadowTest.this.x = " + ShadowTest.this.x);
    }
}

public static void main(String... args) {
    ShadowTest st = new ShadowTest();
    ShadowTest.FirstLevel fl = st.new FirstLevel();
    fl.methodInFirstLevel(23);
}
}

The following is the output of this example:

x = 23
this.x = 1
ShadowTest.this.x = 0

This shows that the innerclass or class B(FirstLevel) is like or similar to the outer class's variables and methods(for it is associated with the instance of the outer class) of class A(ShadowTest).