You consistently do String foo = new String("some string"). This is useless, as "some string" already is a string. Simplify your code to String foo = "...".

You declare some variables far before you use them. Try to declare your variables as close to their point of use as possible, e.g. instead of

 char ch;
 ...
 ch = str.charAt(2);

you could just do char ch = str.charAt(2). The same holds true for pos, value, value1, value2, value3.

Actually, you don't even need the ch variable as you could do switch (str.charAt(2)) { ... } directly.

Some of your variables have very bad named: value1 does not communicate any intent or meaning. Other variables use unecessary abbreviations.

You have certain magic numbers that could be replaced. E.g. in str.substring(pos + 4, pos + 4 + 6), the 4 is actually matchExpDtAI.length(). I have no idea where the 6 comes from.

This code is pure obfuscation:

 value = value.substring(pos + 5, value.length());

 value1 = value.substring(0, 5);
 value2 = value.substring(value1.length(), value1.length() + 4);
 value3 = value.substring(value1.length() + value2.length(),
                 value1.length() + value2.length() + 1);
 value3 = value1 + "-" + value2 + "-" + value3;
 value = value.trim();
 System.out.println("Found string Item :  " + value3);

Note that you don't use the value1, value2, and value3 variables outside of this snippet, so they are unecessary. If we count the lengths of those substrings, we can see that this code should be equivalent:

 value = value.substring(pos + 5), value.length());

 System.out.println("Found string Item : " +
     value.substring(0,     5        ) + "-" +
     value.substring(5,     5 + 4    ) + "-" +
     value.substring(5 + 4, 5 + 4 + 1));

 value = value.trim();

Those constant offsets can be folded, which makes it easier to see that these substrings are actually consecutive:

 value = value.substring(pos + 5), value.length());

 System.out.println("Found string Item : " +
     value.substring(0,  5) + "-" +
     value.substring(5,  9) + "-" +
     value.substring(9, 10));

 value = value.trim();

Actually, let's use String.format for that:

 value = value.substring(pos + 5), value.length());

 System.out.println(String.format("Found string Item: %s-%s-%s",
     value.substring(0,  5),
     value.substring(5,  9),
     value.substring(9, 10)
 ));

 value = value.trim();

You consistently do String foo = new String("some string"). This is useless, as "some string" already is a string. Simplify your code to String foo = "...".

You declare some variables far before you use them. Try to declare your variables as close to their point of use as possible, e.g. instead of

 char ch;
 ...
 ch = str.charAt(2);

you could just do char ch = str.charAt(2). The same holds true for pos, value, value1, value2, value3.

Actually, you don't even need the ch variable as you could do switch (str.charAt(2)) { ... } directly.

Some of your variables have very bad named: value1 does not communicate any intent or meaning. Other variables use unecessary abbreviations.

You have certain magic numbers that could be replaced. E.g. in str.substring(pos + 4, pos + 4 + 6), the 4 is actually matchExpDtAI.length(). I have no idea where the 6 comes from.

This code is pure obfuscation:

 value = value.substring(pos + 5, value.length());

 value1 = value.substring(0, 5);
 value2 = value.substring(value1.length(), value1.length() + 4);
 value3 = value.substring(value1.length() + value2.length(),
                 value1.length() + value2.length() + 1);
 value3 = value1 + "-" + value2 + "-" + value3;
 value = value.trim();
 System.out.println("Found string Item :  " + value3);

Note that you don't use the value1, value2, and value3 variables outside of this snippet, so they are unecessary. If we count the lengths of those substrings, we can see that this code should be equivalent:

 value = value.substring(pos + 5, value.length());

 System.out.println("Found string Item : " +
     value.substring(0,     5        ) + "-" +
     value.substring(5,     5 + 4    ) + "-" +
     value.substring(5 + 4, 5 + 4 + 1));

 value = value.trim();

Those constant offsets can be folded, which makes it easier to see that these substrings are actually consecutive:

 value = value.substring(pos + 5), value.length());

 System.out.println("Found string Item : " +
     value.substring(0,  5) + "-" +
     value.substring(5,  9) + "-" +
     value.substring(9, 10));

 value = value.trim();

Actually, let's use String.format for that:

 value = value.substring(pos + 5, value.length());

 System.out.println(String.format("Found string Item: %s-%s-%s",
     value.substring(0,  5),
     value.substring(5,  9),
     value.substring(9, 10)
 ));

 value = value.trim();